I had the JP2C for a short period a month or so ago. LOVED it in the shop through their 4x12... so much so that I bought it on the spot... but unfortunately at home through my cabs, or through the cabs at the rehearsal cab I go to, it just didn't work and I wasn't willing to drop another bunch of coin (or dedicate the space) on a Mesa 4x12. Killer cleans and both crunch channels killed it, plus the boost and reverb were also great. I'd not hesitate getting one again if I had the right speakers for it. That said, the other two options you're considering are honestly more alluring to me. Tough choice... I'd probably do the 20th Shiva.