I have. I ended up trading the No Mercy and an Ebonite TNV. The No Mercy was a great ball for me, except it just wouldn't carry the ten pin consistently, no matter what I did in terms of adjustments of angle, speed, everything. The TNV just didn't match my game as well as other bowling balls, plus I was concerned about the longevity of that bowling ball. Too many stories of the ball dying even when well cared for concerned me. As to comparing:
I'm right handed, throw a relatively slow shot, medium/low revs, prefer to play the middle of the lane, standing 27 to 30, playing over 15, breakpoint around ten or so.
No Mercy and Epic Odyssey. Odyssey out of box can handle more oil, carries better. With the surface adjusted a bit to 2000 abralon (I say that OOB the Odyssey is closer to 1000)it compares very well to the No Mercy except, for me, it carries better. Both make a strong, aggressive move to the pocket. Both are strong arc bowling balls, not skid/snap. I use the same shot with the Odyssey as I did with the No Mercy with better results. Both soak up oil, but the Odyssey seems to soak up a little bit less...I think. Both need to be cleaned after every bowling session and it helps to wipe them during bowling before every shot with a microfiber towel. I cleaned (clean) both using Track's Clean n' Dull, mainly, at home after bowling, using Storm's cleaner at the alley.
TNV and Epic Odyssey: The Odyssey can handle much more oil oob than the TNV. The TNV is more of a medium to medium/heavy bowling ball, not a heavy/medium to oil ball. Both hit hard and carry well. For me the Odyssey is a more powerful bowling ball. Both make a strong move to the pocket, however the TNV is more skid/snap than strong arc, at least for me. To me the TNV was too strong to play up ten and too little to play over 15.
The Epic Saga will be a little less aggressive than the TNV. It is a true medium to barely medium/heavy bowling ball. I've adjusted the cover just a bit, taking a little of the polish off of it.
Chuck
