I previously tried the Reaper + ET65 combo, but wasn't getting the bass boost I was looking for. However the midtone from the ET65 mixed really well with the Reapers.
I just got a pair of Reaper 55's and I put them over a pair of regular Reapers. This setup sounds amazing and huge. The best part is that these speakers are super touch sensitive, so I have this huge tone at my fingertips and lots of variation depending on how I play.. no matter how much gain I'm using.
The Reaper 55's fill in the low end really well and I'm feeling froggy enough to challenge Vaughn to use the 55's instead of the ET65's to mix other speakers with :)
All 3 speakers are great. I personally recommend the 55's if you use lots of power-amp distortion because they let you back off the bass for a less fuzzy breakup.
Cheers, and thanks for the great speakers
Matias