Last night at our club night gaming I introduced a few folks to BFG (using my Chaos and Imperial fleets). Happily, I have sparked interests and have been requested to provide input on 500 points fleet for Imperial, Chaos, and Space Marines. Here are my thoughts.
When it comes to building the imperial fleet, i think the most important first consideration is what combination of 2 cruisers you can build from the plastic kit (which allows 2 cruisers but due to limited weapon options, it cannot be just any two cruisers you want). The combination are:
a) Carrier build: two Dictators or a Dictator + a Lunar or a Gothic
b) Cruiser build: two Lunars or a Gothic + a Tyrant or a Dominator
c) Battlecarrier build: two Dauntlesses and a Mars
Fleet build option A. The Dictator (220 pts) i think is a great ship because it is an all purpose ship with batteries, fighter/bombers, and torpedoes. All fleets in my opinion should have a carrier. Two dictators would be 440 pts allowing 1 admiral at 50 pts.
Alternatively you take a Dictator and a Gothic or a Lunar. If you companion a Gothic (180 pts) with the Dictator this would be a great combination as the batteries from the Dictator would take down shields allowing the 4 lances to follow-up for the hits. The Lunar (180 to 200 pts) has both batteries (to take down shields) and lances (to inflict damages) thus allowing it some independent action on its own. The Lunar can also be modified to carry a nova cannon (though somewhat unreliable, has great power and a range of up to 150cm!). Total would be 400 to 420 points leaving 80 - 100 points for an admiral or escorts.
Going to 1000 points you can again load up on Dictators but balancing the fleet out with attack cruisers like a Gothic + a Tyrant would be good as well. Between the Tyrant and the Dominator I think the Tyrant is a better ship with more upgrade options. Total of 375 to 395 points and thus room for escorts. More on escorts later.
Alternatively going to 1000 points you can get a Dauntless (110 pts) light cruiser and a battleship (335 - 365 pts). More on battleships later.
Fleet build option B. This would be an attack cruiser build at 500 points, relying on Lunars or Tyrant + Gothic. The Lunar being armed with both batteries and lances allow it to work independently. But since each ship has to finish firing before the next, they cannot effectively combine their weapons (unless squadroned togehter). In addition, they only have 30cm weapons other than the nova cannons. Two Lunars would be 360 - 400 pts.
A Tyrant and Gothic combination will allow the Tyrant's batteries to take down shields and the Gothic lances to finish the job. The Tyrant also has 45 cm batteries which will be helpful against pesky eldars. This build is 365 to 395 points.
Going to 1000 points the fleet will need a carrier of some sort, either a Dictator or a Mars. Again you can alternatively get a Dauntless (110 pts) light cruiser and a battleship (345 - 375 pts). The Emperor would be tempting as a fleet carrier at 365 points.
Fleet build option C. The alternative to fielding a Dictator as your carrier would be to field a Mars battlecruiser (270 pts) and take the required two cruisers to be Dauntless (110 points each). The Mars is not a larger carrier than the Dictator, nor does it have torpedoes to combine with the bombers, but it does have better ranged batteries, lances, and the nova cannon. The Dauntless are sufficiently mobile to protect the Mars' blindspots. This would be 490 points.
Going to 1000 points you can add a Gothic (as the Mars has the same modeling requirement as the Dictator) or a Lunar. Then you will have to either buy escorts, more Dauntless, or buy another plastic cruiser set but be able to only field one (if you are undecided between different cruiser this might be a nice option to build one carrier, one Gothic, one Tyrant, and one Lunar) .
Regarding escorts, they must be squadron from 2 - 6 ships. Thus when you look at their profile you should multiply the weapons value by the number of ships in the squadron as they fire act act in conjunction with each other. All three are pretty good but the Firestorm seems unpopular for some reason.
Regarding battleships, there are actually 4: the Emperor (365 pts is the correct value based on updated FAQ), the Retribution (345 pts is the correct value based on updated FAQ), the Apocalypse (365 pts) and the Oberon (335 pts). Only the Retribution has a move of 20 cm, the rest is at 15cm. The significance is that battleships has to move 15 cm before turning, and their move is reduced by 5 cm by blast marker. The 15 cm move battleships also cannot turn by "come to new heading" special order or if they move through even one blast marker. Of the remaining ships the Emperor is popular for the +1 leadership and the 16 points of batteries it can focus (which may be better than the Retribution). The Oberon is like a more powerful Dictator/Mars and the Apocalypse a more powerful Lunar.
At 500 points take a Devastation (this is absolutely the best carrier in the list, perhaps in the game, based on points). Then take either a Murder or a Carnage. The Murder has lances but it cannot combine with the batteries; the Carnage has only batteries but can get a pretty good amount together). Two cruisers would be 360 or 370 points. Add a chaos lord at 50 points will take total to 410 or 420, leaving 80 or 90 points for upgrades or escorts. For escorts, the Infidels (2 for 80 points) lets you have torpedoes (rare in the chaos fleet) or the Idolators (2 for 90 points) which has superior batteries.
At 1000 points: since you already have 2 cruisers, you can then take a heavy cruiser. The Styx (at 275 points) is generally considered inferior to the Devastation for points value. The 2 remain heavy cruisers are essentially mirrors of each other; the Hades is a batteries ship supported by lances while the Acheron is a lance ship supported by batteries. Between the two, i would probably take the Acheron as it has more turrets and can concentrate both batteries and lances to the front (the Hades cannot). Thus you will have 310 points left. Since you now have 3 cruisers (2 standards and 1 heavy) you can now take a Desolator battleship or a Repulsive grand cruiser. However, since the plastic cruisers come 2 per box, you may want to build either 1 heavy cruiser and 1 standard cruiser (Acheron + Devastation = 380 pts) or 2 standard cruisers (2 Slaughters at 330 pts) along with a warmaster (50 pts), another escort (they come 3 per blister pack (40 or 45 points). The Slaughters are faster than the other chaos cruisers but also have numerous though limited ranged weapons.
For a Space Marine fleet i would recommend at 500 points take 3 strike cruisers and 1 fleet commander (leadership 10). At 1000 points add 1 battlebarge, leaving 90 points for rerolls or upgrades. In my opinion there is little need for escorts as the strike cruisers can turn 90 degree like escorts and are much more durable in a fight. All strike cruisers and the battle barge can launch fighter-bombers so the fleet will be well protected against other carriers.