I've been researching myself and the above posters have mentioned the things I have learned
1) Buy Motorola (they seem to be the best)
2) Find ones that have channels and subchannels (otherwise you will be listening to constant babbles of "Mom...Dad...where are you?" from other people)
3) Do not buy ones that use AAA batteries! If you buy ones that are not rechargeable, then buys ones that use AA batteries.
4) Nice features, but not absolutely necessary: "silent" mode, so you can be notified of a call without everyone hearing you during a show, etc. -- Notifying "ring" that you are being paged
(good when it's noisy and hard to hear if someone is "calling" you)
5) Bottom line -- you get what you pay for!!