Lobo has little to no chance to beat Doomsday, Kurse, The General, Juggernaut, and possibly Colossusnaut as well (if hes got the same physical invulnerability as Cain does). Id go with Hulk over Lobo in the end, though itd be a fight, and probably Lobo to beat Rulk and Grundy more than not (dont know anything about Steel).
Lobo has stood up to Superman and the Justice League. Of course he can take on The General (Who was taken out by a Amanda through a bomb in his head), Solomon Grundy (Who doesn't nearly have as good of a healing factor as Lobo), or Colossonaut. Lobo was eaten by a bunch of piranhas and was reduced to blood, yet came back instantly. Torn in half, had his head cut off, and a hole blasted through by Pulsar Stargrave, yet continued to fight. Never doubt the Main Man,
Healing and Regneration are The Generals main abilities, he can basically heal from any physical damage, anything, in addition to being strong enough to toss Superman around like a ragdoll. Lobo is strong and tough, but not nearly that much so (yes I know he handled Superman very well in their first outting, but clearly Superman didnt know who he was and was taken by surprise, Superman handles Lobo quite well in their future meetings).