Good Afternoon Jopi88,
I purchased a Rega P5 with Exact cartridge last August. I have heard this unit side by side with the P7 and Exact. The P7 has a very "slight" edge in sound quality, particularly detail, but not by much.
I had the Music hall mmf-7 (a nice unit), a Pro-Ject Wood Classic with Blue Point Special (pretty good), an older THOREN TD-125 with Shure V-15 (don't get one). The Rega sounds "WAY" better than any of them. The ease of use, cost factor, sound quality makes the Rega a superb choice.
If buck$ are a key factor get the P5. If you are can swing the extra $$$ the P7 is the way to go. Be sure to listen to these rigs "in your home" with a rega Exact cartridge. It is so good for the money, much under rated and appreciated. Rega made these to mate perfectly with their arms. The new RB700 on the P5 & P7 is great!
I hope this helps,