You're talking totally different markers here. Other than the price, there's nothing really similar. I'd rather shoot an NT w/ a Critical trigger as the only upgrade than a SLS personally. But when you're talking about markers in this type of price range, that's all it is, PERSONAL opinion. Since you didn't care for the NT10, I'd say keep the SLS. NT11 isn't night and day difference, it's just mildly improved in just about every way.