Only trouble ive seen him have is with fighters who come forward usually behind a high guard and a huge size differential (salido) or similar reflexes, speed, and footwork (selimov). The second Loma starts dictating the fight, his opponent is ****ed. To give him trouble you have to be proactive and not reactive to him or what he does, and come forward and fight your fight, not his. Otherwise youre in for a horrific night and will probably quit on your stool midrounds.
There's definitely a shortage of movers around lightweight these days. I think he's equally comfortable either way....maybe more so moving forward and pushing the fight on his terms. He doesnt have huge power so a truly great pressure fighter may get him uncomfortable over twelve rounds because at some point you have to punch that guy off.