One issue is concern about the safety of holding such a transmitter beside your head.
You can use the FCC RX Exposure Guidelines and see what the recommended distance
is for higher powers.
If you get bored, search on Youtube for "900 MHz ham radio" or something like that. There's a guy up in the northeast who's showing off his reprogrammed Motorola mobile rig I think, along with maybe a big battery and a sizable 900 MHz antenna, all of which he's holding and QSOing and laughing like it's all a big joke or something. Just looking at the position of the antenna, and that guy was running some serious ERP right next to his brain at 902 MHz.
I love 902 MHz and higher, but you're right-on about the safety issue of it all.