Originally Posted by bramblett05
Use the knight if your just starting he has offensive skills plus good defensive while the other two go one or another(at least to me they do)
All the heroes can be very powerful
I do agree that Knight is the easiest to use, but as long as you really
focus on protecting and healing your units, while giving them his passive buffs, Paladin is quite good as well - also his buffs are really great with a Knight teammate in co-op.
Engineer also has quite a different play style (with his Craftsman ability you can really upgrade your walls and get towers for cheap - I often focus purely on artillery and towers at first before I build a single unit with him).