Under TT rules, the stock Banshee-3E is... not good. It has the stats of a mech 2/3rds its size. Actually, even for a 60 or 65 tonner, its firepower would be low, though it does have better armoring. The only thing it has going for it is its devastating charge attacks. It's going to be much better in HBS's game with the buffs to the AC/5, giving it roughly the same long range firepower as a Warhammer (actually even better because the Banshee can manage its heat easier), the same speed, and 150% of its armor. It does lose in short range weaponry compared to that mech, but melee is much more powerful in HBS's game, so it's not a huge loss. Also, a high Guts stat will negate the minimum ranges for its weapons, making it a surprisingly good general-purpose mech, its biggest weakness simply being its late initiative.
Discussion of the Banshee would not be complete with bringing up the BNC-3S, because it turns the Banshee into a damn solid assault mech by any standard. By mounting a reasonably sized engine, it can carry a pair of PPCs and the heat sinks to use them; up close it has 4 medium lasers, two small lasers, and an SRM-6; and it also sports an AC/10 to supplement either range bracket. What's more, it doesn't sacrifice any armor to do any of this. It's an immensely powerful mech, and it's a damn shame it's out of timeline for HBS's game by one year.
Looking at the entire timeline, my favorite variant is the BNC-9S2, a devastatingly powerful fire support mech invented in the 3100s. It carries a heavy PPC, a pair of light PPCs, and a Gauss rifle with 3 tons of ammo letting you fire at anything you have the slightest chance of hitting. Its sniping is enhanced by both a C3 boosted slave and a targeting computer, making it deadly accurate, which is good because the only weapon it has that doesn't have a minimum range is a single ERML, but thanks to the short minimums and enhanced accuracy of its weapons and those 95 ton melee attacks, it's a small matter. 14 double heat sinks make it heat neutral at long range, and it carries 18 tons of armor -- almost the max for a 95 ton mech -- as well as CASE in the event the Gauss rifle takes a crit. Its weaknesses are its 3/5 movement in an era when even many assaults are going faster than that, and its light fusion engine and XL gyro making it highly vulnerable to crits once its armor gets opened up. Overall, though, it's a mech no one wants to face, especially when it's part of a C3 lance.