Ok, I am a new owner (02/27/2017), and here is my story and review.
When I was a teenager, probably around 18 or so, I saved up and bought a GR-300. I fell in love with it. Eventually though, I sold it in order to buy my wife's wedding ring. *awe* Well, a few years into our marriage, I got another one from a hock shop. I eventually had to sell that one too, as we hit upon hard times. I gave up as they were getting rarer and I wasn't impressed with newer models.
Well, this year, I had enough left over in tax refund money to get something for myself, so I got the GR-55 and a Les Paul Custom Pro. I've had it a few days now, and have gone through just about the whole thing, on top of reading all the setup docs here.
I am pleased with how this unit responds to my playing, when set up correctly. I have some issues with the GR-300 COSM model, and have come to the conclusion that the particular model is just bad, as I have no issues anywhere else. I have a post about this in the non-sticky portion if you have any insight.
For the most part, I use the COSM models over the guitar output. They seem to be a little clearer, without a lot of the low end crackle and artifacts that I get going straight through my GT-100. You can get rid of some of it with LP and HP filters, but not all. With the GR models, I don't have to worry about it because it isn't there.
I am light padder, in that the synth / string pads I choose to back my guitar models with aren't too heavy. Just enough to add atmosphere or ambience.
The stock patches were ok, for the most part, but some were just silly. I know this is because they wanted a variety of things for potential buyers to hear at the store, in many genres, as well as cut over the din of noise usually present in stores. But still, some of them are nice starting points.
I really like the ability to down-tune without messing with the actual pegs and having control assignments is really nice as well. On a few patches, I set the volume pedal to two assigns, the first is set to cutoff frequency from low to high, the other is resonance from high to low. So I can dial in custom sounds as I move the pedal, from a pure saw wave, to an electronic-like squelch. Keyboardists know what I mean.
It would've been nicer if the control unit and pickup were clip-mountable, once the brackets are in place, so removal is as easy as pressing a release, for storage in the guitars proper case. I am going to have to order an Anvil ATA case, custom fitting for a Les Paul with lining cutout for the control unit.
I am not a really heavy looper, so I didn't mess with that at all. I probably never will.
It's also nice to MIDI out to my Jupiter-50 and use sounds I already have on hand.
I'd give this unit a 9.5 out of 10. Well worth the money. My rating would've been a 10 if it hadn't been for my troubles with that one COSM model. Instead, I use the PCM versions and it works out well.
Thanks for reading. ~Drew