Hi all!i am new to this site but have been a cell phone user since the late 80"s and love to get the newest from Sprint.I have had most of their phones since 1998 and currently have the samsung m610,840,fusic 550,samsung m500 and lg125.
The following is my personal review of the samsung m610:
Pros
better battery life than the m900.
ultra thin style and easy to hold.
awesome qvga screen.
great speaker and speaker phone w/dedicated speakerphone button.(some
people have complained of speaker crackling at high volume,but not in my
case).
extremely easy to use keypad-I have arthritis and have found some phones a
little difficult for texting but this phone is a breeze.Very well lit keypad.
Bluetooth-very important feature to me and it works flawleesly with the
samsung wep 200 headset.
Camera-2mp and it takes great pictures.I f you do an indoor pic make sure
you hold the camera still for a split second after you take the shot.No
flash but most cell flashes are nearly useless anyway.
Camcorder-on par with most high end phone camcorders.
Memory-about 35mb of usable internal memory and works well with sandisk
1 gb card.
Music player/media player-works very well and sounds great with headphones
or through car speaker system with adaptor.
Menus-very user friendly and has programable favorites key.lots of menu
options.
Browser-very fast and this phone even allows data roaming which,to me,is
extremely helpful since I live in a fringe area.
Advanced voice recognition-very accurate and it automatically sets itself
for each of the up to 500 contacts in the phonebook.works very well
with bluetooth.
Signal strenth-as good if not better than any sprint phone I have ever had.
signal strength should not be an issue for anyone that already has
a decent sprint signal on any sprint phone.
Roaming-can be automatic or you can force it manually.
Downloads-I have downloaded many ringers,screensavers(animated included)
and applications and they all seem to work very well.
Cons
battery life could be a little better for very heavy users but fine for me.
a small bug when scrolling to assign a ringtone or caller id pic,but nothing
that can't be addressed with a ota software update.insted of scrolling
just press the # ie;1.screensaver 2.contacts 3.incoming call.
only one external port for charging or headset.no big deal because adaptors
are readily available on ebay.

I think I covered most everything.I will probably keep this until sprint comes out with a blackberry like t mobile just came out with(very tiny).i would recommend this phone to anyone with sprint service.
Hopefully this review helps someone considering the M610.