Figured I'd do a quick state-of-the-game update.
Nov 6 PGI pushed a patch that broke LRMs. They added Artemis IV, which tightened weapon groupings, and they managed to bug the flight trajectories, making LRMs essentially ignore cover and preferentially hit the head and center torso of targets. They immediately recognized the problems this caused (basically, it was go LRM or go home in a body bag). They rushed a hotfix on the 8th that made the LRM flight paths pretty much exactly how they need to be, plus they reduced missile damage and widened spread.
The next major patch is scheduled for the 20th, where they will add the Cataphract mech, DX11 support, and possibly some other goodies (like weapon tweaks, another few new maps or map variations, etc.).
Current weapon balance favors the Gauss Rifle. Small laser weapons work nicely too, since they and the GR are the things least crippled by the heat system. Larger lasers are seeing more use with the current implementation of Double Heat Sinks, but PPCs and ER weapons are still a rare sight. The very light autocannons see a good bit of use due to very high sustained dps and constant screen shake from rapid, repeated projectile impacts, but the larger ones (AC10 and AC20) are very rare, since the smaller ones have more range, better sustained dps, and more efficient damage for the tonnage, while the Gauss supplies a long range, very low heat, very high damage alternative. LRMs are a bit weak right now, but they can still do plenty of work and garner kills. Their biggest problem is that they require teamwork to be truly effective. SRMs are in a good place (and have been for several months now). Streaks are broken, but a fix is coming. Machine guns and flamers are dead weight.
Projected weapon balance tweaks include accelerating bigger ballistic projectiles to make them easier to aim, adding significant screen shake to the AC20 when it hits you, and making the GR a very fragile gun that has a good chance to blow up catastrophically when it gets hit. LRMs are also supposed to be getting a slight damage buff. MGs and flamers are eventually going to get a bit of a rework/buff to make them more useful. Finally, PPCs are planned to have a bit of a heat reduction and an added emp-like effect on targets (one would guess that it'd screw with the HUD and targeting capabilities).
All in all, c-bills come in steadily, and since individual matches are so short it doesn't take much actual time to earn enough cash to buy a mech and kit it out however you want. The game still has occasional stability issues and the netcode is not ideal, but if you have a low ping you don't tend to suffer for it (the effects are amplified significantly for high-ping players, or so I've heard; my ping is always super low).
Light mechs are very popular now, in part since people flock to whatever they were last killed by, in part because collisions and falling down are temporarily removed while PGI tries to fix some nasty rubber-banding issues that were making knock-downs really dumb, and in part because of netcode and high-ping lag-shielding.
It is probably in the most balanced state weapon-wise since I've been playing, and it looks to be getting even better with each subsequent patch at this point. Plus, the modified Forest Colony and the added Forest Colony Snow maps are quite fun. A Desert map should be on the way soonish, and night versions of the other maps are likely as well. The 20th is the next scheduled patch time, but in the mean time it is eminently playable.
The game is still free, and is quite fun. Currently, group queues are limited to 4 or fewer players, and teams are 8v8. Solo queue is viable, but can be painful. The game gets more and more fun the more people you queue with, especially if you have a voice chat system that you are all using. If you do sign up and want to play, the best thing to do is bring a friend or three along.