[kindly skipping the thread]
My personal experience with amp sims are on my Digitech RP150. I use it quite a bit, since it's extremely easy for PC recording. I've been using it for years and I've never had a single issue with sound quality, driver/software support, recording and the like. So, I love this thing.
With that said, the RP150 (and many other RP models) include a bunch of amp/cab sims. I actually have never assembled a tone with a certain desired amp in mind... every tone I've made was simply the result of tons of tweaking to make a tone that sounds good to me. What I mean is that I develop a tone using the Rectifier amp sim with a Bassman 4x12 cab sim (just an example). I did that because it had a tone range that sounded like what I was targeting; I didn't say to myself "I think I want a Rectifier tone".
So what I'm saying is that as far as going for accurate replications of these amps using the sims, I don't really have an opinion, since I don't really use it in that fashion. I just develop specific tones for what I need in parts of my music, regardless of which amp/cab sim it takes.
(hope this makes sense, lol)
EDIT: I used the Digitech RP150 entirely on my Algarothsyum album (see my signature below). I recorded all guitars and bass tracks with it. I also used it on the Algarothsyum 5-track demo as well... I even recorded V-drums through the Digitech. So with the results and service I've gotten with my processor, I'm VERY satisfied. For the new material I'm recording now, I still use the Digitech, although I'm using it purely as a recording interface. I record with my Line 6 Spider II, direct output now. So the Digitech still serves me well, especially for other effects.