Pros Good for a paper weight only.
Cons Aside from a paper weight, everything is a con.
Summary Perhaps I am bias; however, this device does not work at all with the Treo 650. Awful sound and unless I held the phone next to my ear, which defeats the entire purpose of blue tooth, it was full of static.
Pros Inexpensive and quick set-up
Cons non-replaceable battery should the battery fail
Summary Ok, I bought this in conjunction with my Treo 650 (see my profile to read my review on that) and I would recommend folks buy something else if you are using a Treo.
I get too much static to use for day-to-day use and that’s with the headset less then 3 feet from the device. There is no distance issue, it’s a product issue.
Since I have not purchased another Bluetooth Headset, I won’t know for sure if it’s the Treo or the Headset causing the static. Until then, stay away from the 2500 if you are using a Treo.
Pros Looks cool
Cons Bluetooth signal range is super short and battery dies quick
Summary Well I'm using a Sony Ericsson (Bluetooth enabled) T616, so I don't know how much to blame on the phone, but it does "recognize" the M2500 by name. However, I can only get 25 minutes of time on the headset battery. I have tried "reinitializing" it with the phone, I traded it in for another of the same model thinking the first one was defective, and I tried turning the volume down as low as possible to save the battery. Nothing has worked. Also, I am lucky if I can walk more than 6 feet away from my phone--far less than the "up to 30 feet" claimed in the literature. If I have the phone in my belt holster or pocket, there is some effect on the sound quality--a distortion like the sound of wind blowing accross a microphone. Also, the rubber ear insertion pops off too easily. Don't try to keep the headset in your pocket for when you need it to drive--you will be fishing around for the ear bud after pulling out the headset. Finally, although the device is well balanced and the concept of hiding the battery portion behind the ear is smart--I have trouble having it fit on snuggly--my own ear thingy gets in the way (and I think my ears are average). Oh and I almost forgot--turning the device on means pushing a recessed rubbery wheel straight down, and holding it for 2 seconds. Don't let your fingernail slightly spin the wheel, or it won't turn on. What a pity if some motorist ends up in a bloody car crash in the attempt to turn on their M2500 hands free device -- made to help avoid bloody car crashes. I wish I could say something more positive about the M2500--I'm not usually this negative about a product. Sorry, buy a different brand or model.
"Nice design"on by viachipset
Pros Modern design, nice look
Cons Noise, noise and noise
Summary Even if I hold the phone on my hand the M2500 still having static noise. Don't be cheap like me and go for a more expensive one with good signal range.
"Very good headset"on by hazzard1
Pros comfortable; great sound on the receiving end; affordable; good battery life
Cons could have a noise canceling microphone
Summary What most people here seem to ignore is that the earpiece is the slave device that gets commands from the master (the cell phone). A cell phone with a poor Bluetooth adapter will affect the sound quality on the headset. Keep buying crappy Treo cell phones and suffering. I have no problems using this headset with my Nokia 3250. Having in mind it's a discontinued model from Plantronics that was launched to the market 3 years ago, I can say it competes with the most modern headsets you can find in today's market.
If you still find it, buy it!