Did my first gig this past Saturday with the new band and Rumble 500. Overall? VERY impressed! All I had was the 2x10 combo and there was no lack of low end or clarity whatsoever. The on board EQ and different voicing options are very musical, and with the added tweeter on/off option there's no lack of crisp top end. In fact, midway through the set the percussionist asked if I could turn down a bit. (Still getting my feet wet with overall band blend, various rooms, etc). I ran the Eden Navigator through it, and that only helped tighten up the sound. I also went DI into the board, but one caveat of the Rumble series is the DI is post preamp, so I ended up going DI via my Eden Navigator instead (which has multiple DI post/pre options). Yesterday, I received the matching 115 cabinet (which also has a tweeter on/off option) and combined with the Rumble 500 the sound is absolutely monstrous. Plenty of power and volume, especially for a class D. It's probably way more than I'll ever need, though we do have an upcoming outdoor beach show so I might need to bump it up a notch.
It doesn't quite compare to my Eden Navigator/Eden 4x10XLT (If only that damn thing wasn't 98lbs!), but it's respectable in it's own right. I highly recommend the Fender Rumble series for someone looking for a good, powerful, and "organic" sounding lightweight rig on a budget. And it looks so cool too with it's retro Fender blackface appointments
I got my old GK 400RB head fixed and when A/B'ing the GK/Eden Navigator preamp + Eden 4x10" to the Fender Rumble setup, the improved sound was noticeably apparent: tighter low end, improved clarity. I returned the Rumble 500 but kept the 1x15" Rumble cabinet only, since I am still in need of a lighter weight setup for those occasions. (I still recommend the Rumble series for anyone loping for a good amp on a budget). The GK head straight into either cabinets sounded pretty awesome too, so I may decide to just leave the Eden Navigator at home for certain gigs. I do like it's on board compression and EQ though, so maybe I'll be looking for a good compression pedal instead. 