I own a V51. Following is what I know.

1 It is OK but it does not work with GPRS card. I heard that the new update fixed the problem.
2 The quaility of its screen is "JUST" ok. Why? It is because its screen has serious "Newton Ring" problem. If you don't mind it, it is still good.
3 In addition, you have to install Chinese system by yourself (CE-star). CE-star is useable but not very stable. I never receive any CE-star update for almost a year.
4 WM 5.0's office application is very good.
5 It is very slow if the application is not loaded to RAM yet.
6 Pocket IE is still very bad, and you have to install opera.
7 Finally, I also heard that DELL dismissed its PDA team, so V51 will be the last model.

One more thing. If you want to buy v51, you should check the price carefully. Sometimes, Dell's price varies week by week. The lowest price can be as low as 28xx.