Plantronics M2500 vs Motorola HS801

My husband and I both have the Nokia 6230 phones. We want a bluetooth
headset each. Which of the above is better? And if we both get the same
one, will it be a problem if we are in close range of each other (as in the
car), or when pairing the device, does the phone pair to the specific
headset or just generically to the headset model #?



Thanks,

Carol Van