Toyed around with the Power use this weekend. I have had it on for as long as I can remember so I don't even recall the lower RPM shift points and how they felt. Especially since I put in the S/C. In all seriousness, I previously really had no clue as to "how the VX operates with Power OFF".
So, I turned it off and headed out on the backroads and the highway. Damn, I gotta say, it shifts so much smoother and elegantly. I couldnt even feel it shifting. It made casual driving very comforting. However, even with the S/C, you can forget quick highway merges and passing. It just wouldnt downshift fast enough and hold the high RPMs before shifting back up to be worth it. With the Power activated, downshifting on acceleration is near instant and holding high RPMs before shifting up (as well as the boost from the S/C) is a very positive reaction for spirited driving.
In conclusion, on days when you have a sweltering need for "driving it like you stole it", Power ON is gonna be your answer. When you are just laid back and looking to have a nice, smooth, relaxed ride, Power OFF gives you just that. And I must say, since I drive the VX like a fragile egg, I have found a liking for the OFF mode. Those light, smooth shifts really have me that Cadillac TOD feeling, heh.