as mentioned FCC regulations pretty much dictate performance. And FCC has cracked down on the radios that gamed the system and never really were FCC legal. Now they are pretty much band specific (GMRS, FRS, HAM, MURS) several require licenses.
With handheld units expect pretty much line of site use. Performance wise most brands are going to be pretty much equal. Ruggedness and accessories is the major difference. Go up in quality and you get weatherproof or waterproof, more rugged cases, interchangeable battery packs, high capacity battery packs, antenna choices, tone controlled squelch, voice scrambling, setup for in the helmet headsets etc.
As mentioned HAM units will often give you the ability to use repeaters to increase distance. today getting a ham license for the units is much easier than in the past.
We been using a setup with in the helmet mic/speakers, bar mounted push to talk and tone controlled squelch for motorcycle riding for more than a decade. Range has varied from about 1/4 mile in dense woods, to a mile + on open level straight highway. We've tried MURS, FRS, and GMRS channels. We've found for the terrain we ride in MURS give us a bit better performance then GMRS or FRS for the same output power. MURS is near the 2m ham band. (154ish mhz)
When we are out camping, the radios are good for campground communication, that's about it. campground to a hiking trail, not to be relied on.