You've picked the two best as it is, so you're on the right track. The only other good modern one to look at its he FWL's LGR toating 5M, but most people don't have a school girl crush on the LGR like I do and so don't like it quite so much.
Between the 4S and 10S, its a fun contest, since they do largely the same things but in difrent ways. The tradition of the Battlemaster is a mech that carried a weapon with some range, so as not to get laughed at like the Atlas (which by the way carries a LRM 20 with more power and range than the Beemer's PPC) but is really meant to mix it up in close. Its got a bit of speed, a big array of MLs, lots of heatsinks, and a pile of armor.
The 4S keeps the speed, uses a GR at long range, but since the GR's got no heat it can stay on line in close when the four well sinked ER MLs and SRM6 come into play. Its also got significant armor and a durable light engine. Conversly, the 10S takes the durability up a level with a compact engine and a heavy gyro (a bit of tech I adore). Its back to a PPC, and despite the huge heatsink array the PPC pushes it over the top in close, leaving most of the work to the six ER MLs and SSRM4. Its tougher, with similar power (it depends a bit on how much you want to push the heat) but slower, despite being more short range focused. I prefer the 4S, but I prefer fast and quick battles, which the ammo based, high speed, LFE packing 4S excells at. If you like a longer, knock down drag out battle, the 10S has basicly no ammo worries (its only ammo weapon is a streak launcher) and fewer critable components that can take it down. Its pretty close between them.