The thread I posted about the preference of vintage over modern gear relates a lot to this thread. I don't think any amp modeler can duplicate the old jazz and blues tones used in the 40's 50's and 60's. For that you need to get yourself a vintage amp. The modelers sound like they are poorl imitating something when you try to get that sort of tone out of them.
Fortunatly for me, I don't have a need for that tone. But I do see how someone would want that.
My vote goes for - you get what you pay for. Cheap is "good enough", if you can tolerate your sound being just "good enough." But then you also need to look out for the overpriced brands too. In my opinion, no amp on earth is as overrated as Marshall. I've heard several CHEAPER amps sound superior. But it all depends on what you like to hear. In general, the quality of the sound goes up along with the price tag.