I primarily use it with a Les Paul and an Ibanez Hollowbody. Both guitars use humbucking pickup's that were made by GFS (great pickup's for the price and I have played numberous pickup's over the years. The only other pickup's I ever use are EMG active's that I have to use when I play metal). Overall the sounds I get out of are very good. However, I did do some modifications. First, I made a new back for the cabinet and made it an open back. I personally like the sound of an open back cabinet and found the amp originally far too bass heavy. Good if you want a really fat tone, but I like a nice and airy tone (to get anything I liked before this mod the bass tone was always on about 3 or so). The second mod I did was changed the tube to a Sovtek. Sovteks are generally worse then the Electro Harmonix that is in there. However, I like the nasally/compressed sound that the sovtek gives me. It sounds a little more vintage in my opinion.
I also have an early 70's Fender Twin Reverb and this thing comes very close to that sound with the "blackface 2x12" setting. Although you won't find yourself using all the amp models, some are obviously better then others, all of them are fairly good and can be used for something. There is no model that really just sounds horrible. They all sound better than any transistor Marshall you could buy today.
The only thing I find about this amp is that it is a little on the quiet side for 50W. I don't understand how they could call it a 50W amp when they say that it only uses 52W total power for the whole Amp. That is around a 96% efficiency which is impossible for any amp, even a new digital amp.
Before the mods I would give this amp a 7. After my mods I give this amp an 8.
I have had no problems that others have reported. My amp does have a fan in it, but what can you do. Most of the amps that are built today in this price range have a fan. I was planning on disconnecting it and installing a larger heatsink one day. But, so far my fan is very quiet, even in my room when I am practising. From my experience I am going to give it a 10 in this area. However, others have not had my luck. Just so you know, I usually jam and gig with this amp just about as loud as it will go and I still have had no problems.
I would not hesitate to gig without a backup. You don't want to become a gearhead with more equipment than brains at a gig.
Overall this is a great little amp. Its not perfect, but no amp is. Its not getting perfect scores from anyone but those that won't admit that it has flaws. However, I can find flaws and problems in any amp. This amp is more versatile then most, that is such an advantage for someone who is a working musician. If you are a true tube head then you don't care about versatility. That's fine, stick with your one sound then. In that case this is not the amp for you. But, for those of us who play a lot of different music, this amp is great. I am in a 60's and 70's classic rock band(everything from CCR to Black Sabbath) and have been able to recreate a lot of the sounds from those songs. In my opinion that is worth giving up some of the vintage "tube" vibe for a good mix of tube and transistors (plus that, I don't miss paying for new power tubes all the time. The preamp tube will easily last 10 years if not 20 or so).
I have been playing for around 18 years and have always wanted a versatile amp like this. I only keep 2 amps around and can get most sounds I need out of them, this one and the Twin Reverb. I use the Twin now and then for sounds and when I need to be really loud. But, for the most part this is my amp.