MPLS ???

Hi guys,
Currently we are running SBS2003, we have two T1’s connecting our two retail locations to our corporate office. We have PRI with BCM 400. We have one Internet DSL 1MB connection that is shared by all 3 locations. The VoIP travels on the T1…… ok now, I’ve have two vendor contact me about switching over to MPLS. I have never heard of MPLS before, Im new in the industry. Anyone have any experience with this technology ?Would you recommend it as a replacement for what we have now??? The main issue is speed and price.

THANKS