I don't have too much experience with, really, any lens but I absolutely love the *50-135. I'm on my second (after I tried to fix a broken gasket in the first but ended up irreversibly disassembling it) and if it completely failed tomorrow, I'd get it repaired or try to get another one. It really is a lens that I take everywhere. If a version II of the 50-135 is released, it would definitely end up on my "will definitely buy sooner rather than later" list.
This was one of my first pictures taken with the 50-135. Compared to pictures shown here, I can't even compare them, but, for me, it kind of shows why I love this lens. I think this was mostly SOOC with a few edits done.
I also have a *16-50 (my second after getting a used dud from UsedPhotoPro) and a *55. I haven't really used the 55 all that often because I find the focal length to be a little long most of the time but I prefer having a fast lens in the 50mm range. I'm also still getting used to the 16-50 and it's quirks. It's become my 'always-on' lens because of its convenience but also because it fits that way in my bag...
Honestly, I really like the Star lenses and the quality they offer. I also really appreciate the level of weather sealing they offer and, knowing me, I'm going to need it one day just on accident or out of sheer incompetence.