I bought the Scala 500 today and was a little worried that I wouldn't like it. I read the reviews between the Scala 500 and the Motorola HS850 and decided I was going to get the HS850. The resons behind this was not only the price being lower, but my boss has one and he hasn't had one complaint with his. He had it paired to his Razr and now his HP6515.
I was all set to get the HS850 but the store near work had already sold out of them. I opted for my other choice, the Scala 500. Well I read the quick start manual to find out I had to charge it for 4 hours on the first charging then 2-3 hours every charge after that. 4 hours?? It was going to take me four hours to find out if I really would like it.
Well, four hours later I get it paired in less than a minute, so setup was a breeze. I called a buddy of mine who is as picky about quality as I am when it comes to electronics. He said that it actually sounded better, more mellow, and smoother than the built in mic on the phone. This pleased me alot to hear that from him. I got home and called the wife to see if it would work while the HP was in the craddle, Badda-bing, it worked!! Then I walked around the house and got to the other end and it never lost contact with the Pocket pc. It did how-ever start getting crackly about 35 feet away. I haven't figured out why some reviews I read had said there is alot of static in the ear piece. I haven't found that to be true yet.
When a call comes in, there is a little beeping type tone that I hear instead of the ringtone of my phone. I will be curious if this still works like this if I turn my phone on silent. I will have to edit in the answer later.
//edit// Yes it does work while the 6515 is on silent. The wife called me the other night and the earpiece tone was the only thing that sounded off.//
All-in-all, I am very satisfied with the performance of the Scala 500 paired to my HP6515. I think they were a match made in electronic bliss.