Two-way suggestions for large meetings

I am researching different two-way radios for the use at large meetings and conventions all around the world. Most are in major cities. I am completely new to world of two-way radios. We need approximately 6-10 total for our on-site coordinators. We would like portable earpieces for each as well. Can anyone suggest the best make and model for us? And why? Thanks in advance!

depending on your budget. 2 good options

trisquare two way radios
Motorola SX600R 2-Way FRS/GMRS Radio