That's sort of a loaded question. Some provider's offerings are good
for different reasons/have different strengths. Your best fit would
depend on your individual needs.
How many sites will you have, and what is your access method and speed
preference?
Do you need granular QoS from CPE to CPE or will queuing on the access
loop suffice?
Prefer or require layer 2 (Martini, Kompella/Lasserre, etc.) MPLS vs.
layer 3 (2547)?
Do you need the service to support multicast?
Does your WAN require the service to support an IGP (OSPF, RIPv2, etc.)?
Do you require internet access over the same access loop?
Require the provider's network to be physically separate from the public
internet?
Plus many more...
The answers to these questions should significantly narrow your choices.
Bryant Rump