I´ve had my F700BT for 2 months now and I´m already used to the slow boot time. To buy it or not??? ...It all depends on what your priorities are, mine are
1. ipod integration: I think is one of the best, if not the best on the maket, the interface looks awsome with the album art and the ipod wheel and its decently fast.
2. BT hands free: many people have complained about this but for me works just fine with my nokia phone.
3. Interface: although the touch screen is not as responsive as you would like (like an iphone or an itouch for example) its OK but what I really like is the look of the menus and the icons and it´s ease of use. I think there isn´t a unit in the market that looks as good as the F-series, IMO.
4. SD slot: A big plus, specialy for the F700 that doesn´t have a DVD drive, I´m not a fan of watching videos in the car but with an SD you can load some if you want.
5. Hackable: Very interesting if you like to personalize your unit with new icons and backgrounds,
6. Navi: I bearly use it so I´m not the person to comment on this. you might want to look nore info on this.
Yes, it has minor bugs, it boots slow, but overall, in my case the above stuff overcomes all the problems and makes it a very good unit with lots of potential. You also have to have in mind that this is a "PC" running windows CE 5.0, good in the sence that some very smart members of this comunity have been able to fix some pioneer mistakes and make it posible to modify some stuff, and bad that it might be what makes it boot so slow....
This is all my opinion and my experience as you might also read some very bad posts of very angry people saying that this is the worst unit ever....
Learn some more and make your desition. Hope this helps.