From a HBS/MW5 POV here.
The steiner lance has a mech that i will use into end game, the Griffin S. It has good weapons hardpoints, bit harsh on too much in RT arm, but a great design overall. All the other lances will entirely be replaced as quickly as you salvage mechs, so by mission 4 you likely have an entirely different team.
From a classic POV, the Griffin is the 5/8/5 paragon 55 tonner, and the S rates only below the Wolverine M (and I am of the opinion that the Griffin S is better then the WolvM). The locust is solid in classic, and for RPG campaigns with quirks it amd the commando are low profile which is awesome when starting out.