I am assuming you stoped playing after Phoenix but before Clans, while almost all Mech released since then are viable the best of them are:
Urbanmech, 30 ton IS light (available through preorder only, no release date has been announced for cbills), widely considered a bit of a joke, but it has 360
o torso twist and is great fun to pilot, released due to popular demand
Kit Fox (Uller), 30 Ton Clan light Mech, can mount 3 AMS, an ECM and Jumpjets while still having about 8 tons left over for other weapons. makes a great umbrella protecting your team from missiles and providing stealth
Firestarter, 35 ton IS Light, very durable even with an XL, can move 150 with speed tweek, can jump, has up-to 8 energy hardpoints, and is currently considered the best Light Mech in the game
Enforcer, 50 Ton IS Medium, designed for Balistics
Stormcrow (Ruyken), 55 ton Clan Medium, fast, agile, plenty of space for weapons, infinately customizable weapons configurations thanks to Omnipod system, arguably the best Medium (and 2nd best Mech) in the game, the only downside is it cannot mount Jumpjets
Helbringer (Loki), Clan 65Ton, can mount ECM, and has a good range of hardpoints available
Timber Wolf (Mad Cat), Clan 75Ton Heavy Mech, fast and agile for its size, can mount Jumpjets, great balance of speed, armor and firepower makes it arguably the best Mech in the game, but most players know this, piloting a Timber Wolf is dangerous because the enemy will target you over almost any other Mech
Dire Wolf (Daishi) 100 ton Clan assualt, has more tonnage for weapons than any other Clan Mech, it can mount a wide variety of weapons and has a lot of possible configurations thanks to the omnipods. it can bring overwhelming firepower against anything in front of it however it is really slow and unmaneuverable, if anything gets behind you it will probably be able to kill you with little effort.
King Crab, 100 Ton IS assualt, released to give the IS something which can mount multiple large ballistics (each arm is able to fit an AC20) and additional backup weapons
Clan Mechs can swop "Omnipods" (hardpoints and fixed equipment for individual body parts) between variants (can swop any omnipod except CT) but cannot change engine, structure, armor type, heat sink type, and many Clan have other fixed equipment (e.g. a Flamer on the Adder, loads of heatsinks on the Warhawk, an AP on the Mist Lynx) if a varient has Jumpjets those are fixed to the omnipod so if all variants have jumpjets you are stuck with them and you add jumpjets by adding an omnipod mounting them (assuming one is available)
Edited by Rogue Jedi, 07 May 2015 - 07:28 AM.