Okay. I owned and played with the Wilson HPS 5.0 for some time. I demo'ed the standard 27" version and when I went to order one the guy at the store convinced me I should order the stretch with a 27 and 1/2" length. I didn't like it as much as the standard.
But, in general, it is a very good racquet but quite stiff. I used the stretch version with a good synthetic but if I were to try it again I'd use natural gut strings (with the string savers) and string it at about 52#. With synthetic strings it can be kinda' hard on the elbow.
There was a guy who played in the final of the French Open several years back and he used the HPS 5.0. Played Keurten. Some guy from Sweeden. I'm sure somebody knows his name right off. Anyway, he obviously did quite well with it. Interestingly, Keurten (who won) used a Head iPrestige of some sort. Great match!
HPS 5.0 is a stiff, heavy, players racquet. You need to be in good shape to swing it for a 3 set match since it weighs over 12 oz strung. Pick a softer string (gut, NRG, Bab Excel, etc) and you should be ok.
i.prestige MP is a little lighter weight, more flexible than the 5.0 and lower powered - but still enough to put away groundies and get a few aces if you are a 4.5 and above.
I prefered the iprestige MP just for added comfort over the HPS 5.0. It's all relative to the player though - my buddy just bought 2 HPS 5.0 since he loved the frame when they came out years ago and hasn't played with anything better since so he bought some before they are extinct.
I'm not sure what hyper 5.0 Richie Rich is talking about but the one I remember, the grey and maroon one was not heavy. It was about 10 ounces unstrung. Like RR said, it was very stiff. I have a very sensitive elbow and it was aggravating my elbow within 2 or 3 groundstrokes.
I have a HPS 5.0 stretch and I really liked it alot and I could bomb serves with it. I actually used poly (babalat ballistic) at 62lbs and I didn't think it was hard on my arm at all... I do agree that you have to be strong to swing it being a 12.3-4 ounce racquet. To me I found racquets with dense string patterns to be harder on my arm especially with poly strings. I tried the I.prestige with poly and I found the combination of poly and dense string pattern to be kind of hard on my rist. But not a bad racquet. However if I could take my pick I would take the 5.0 over the i.Prestige.