I'm using the RP500 and compared to some of the other Line 6 etc available, this one does justify the word "modelling".
However, I AM using the amp/cab simulator quite heavily as thats one of the good features. I wont go and say it accurately mimics a $2000 Marshall, but it does come very close.
The effects offered are good. The best feature I find id that u can use the 5 footswitches in 2 modes. In normal mode, you can assign a patch to each switch, and so u can have a clean fender champ with chorus and reverb on 1 footswitch, and pressing footswitch 2 will take you to a chunky marshall ballsy rhythm/blues tone. the third switch might be used for leads and somehting and so on.
In the pedalboard mode, each footswitch acts as a stomp box. So you have 5 stompboxes namely the compressor, distortion, chorus, delay and reverb laid out. and u can switch each one of them on and off. Combine this with simulator bypass and a good tube amp, and you'll love the tone it puts out.
Im not too sure how accurate the stomp box models are, as I have never played on actual boxes, but they do sound good. U can always use distortion as lead boosts in your setup.
At $300, its worth buying IMHO.
My gear, currently up for sale
Washburn X-16 anarchy - SOLD!!
duncan pickups - I wonder why Im selling these.