Im loving the game so far. My favorite mech so far to play fun wise is a dragon with a XL 400, a ER PPC, and as many heatsinks as i can fit with remaining weight. Nothing scares a jenner more than chasing him around in a heavy that can do 108kph and shoot a ER PPC at him ever 2 seconds. I generally hang with the missleboats and fend of the lights with the ER PPC, works very well as a few good shots with the PPC will down a jenner or commando in short order, and you usualyy get at least 2 or 3 good options at shots on them before they realize you can keep up with them, no one expects to see a dragon moving at 100+.
My favorite build for a assault is a atlas with a LRM 20 and 2 large lasers, and a AMS system, im actually using the varient now that allows 2 AMS systems so missles dont really effect me anymore. This allows me to hammer on them with the LRM 20 as i approch and then chop them up with the lasers, im running enough heatsinks i can fire as fast as i can cycle the lasers and not worry about heat. Also its fun to rain down LRM on their missle boats while also engaing there assault mechs close in.