I have a Gibson SG (solid walnut - heavy with loads of sustain) and a Fender Blues DeVille (4X10) with 12AX7LPS and 12AY7 preamp tubes. These are all very quiet, and the Digitech does add a bit of noise, but very little. I have a hot Dimarzio super distortion in the bridge, so I don't needs to use any gain on the RP-5, so noise really isn't an issue. I am unsatisfied with the raspy, ditital-sounding overdrive on the RP-5, and use a separate pedal (Bad Monkey - poor man's Tube Screamer) for smoother light overdrive (bluesy tone). If I want to crank out distortion, the combo of the pedal and the RP-5's heavier distortion and the amp's tubes works great together to get the smooth, searing sound I like for soloing (ala Satriani, not that I can play like him). I think the delay, the chorus and the reverb are as good as any other unit and sound very professional. Again, very customizable. I haven't used the cabinet emmulation/stereo effects except though headphones, which actually sounds pretty awesome. I got a DOD volume/wah pedal to control the RP-5's Wah - I use the DOD's built-in wah instead of the RP-5's which sounded laughable to me. Again, the distortion sucks through headphones, except heavy distortion but then playing through headphones sucks in general. But the wife needs her sleep.
I have never had a problem with reliablitly with the RP-5, and I use it every week without any concerns for a backup.
I have been playing since 1978, rock, blues, fusion-y jazz, have owned a few pedals (Morley Wah and flanger, MXR Disortion +, envelope, DDL, Elecroharmonix Big Muff Pi, small stone, Ibanez chorus...etc... For all those "vintage" effects, this unit is a good substitute. When it dies, I will likely go to a music store and try out a bunch of stuff before deciding on anything. I get setting s that I love with this unit, and really, your playing will make more of a difference in how you sound, so stop reading and go practice!!!