Been down this road several years ago. Spent a lot of money, tried many models and styles and for whats it's worth here's what we learned.

1. Simply put handheld radios by FFC regulation can only transmit at a max pwr of 5 watts.
2. All transmission are line of sight without a repeater system installed.
3. Most over the counter handhelds have a difficult time transmitting at that rate for any length of time without a significant battery. Quality battery = $$$. Therefore most radios you find at your local sporting goods store are transmitting at something less than 5 watts in an effort to conserve battery life.
4. All the claims of 18 miles, 24 miles radio etc... LOL...LOL..... Remember, when testing a squelch break is considered a transmission.
5. Trees, terrain, weather, etc. all absorb RF signal thus reducing range. The transmission is traveling in a straight line so anything in it's path takes a chunk. Keep in mind the curvature of the earth starts kicking in at 3 miles so how they get past that has to requires one unit significantly above the horizon.

After hundreds of test; Average range when standing on the ground (moderate hills, average hardwood forrest) where 90%+ transmissions were received came out to 1/2-3/4 mile.
1 mile coverage occurred less than 25% of the time.
Over 1 mile rare.

Additional observations The $400.00 name brand hand helds really didn't perform any better that the $100 a pair units at BP or Dicks. I use a $2000 handheld everyday and without repeaters when used in a line of sight mode we get maybe 1/2 mile.

Now what you can do if you hunt in the same area all the time is stand up a Base Station in a central location. We did this at our club house which was in the middle of the farm in the wide open and allowed for placing an antenna 50 ft in the air. This enabled someone at the house to relay transmissions across the farm, plus reception was much better with the high antenna. If you have the $$$ you can stand up a repeater system but that going to run you a right good chunk and theres going to be some Lic. requirements.

As far as which unit to buy off the shelf? It all comes down to features. I suggest buy ones that accept standard batteries. Re-charge batteries tend to not put out as well as higher end standard batteries and you can't re-power in the woods. As far as call features and everything else, most rarely get used and actually become a pain if your don;t know how to shut them off or get the buttons into the locked mode and don't remember how to unlock them.

Hope this ramble helps....