Multi-Protocol Label Switching (MPLS) is really beneficial for ISPs to quickly forward traffic based on 1 to 3 labels inserted in the packet header (between the L2 and L3 info).
It differs from “regular” ISP connections in that it doesn’t need to read the L3 (IP) addresses to forward your traffic. PLUS, the MPLS tagging (labeling) is only good for the MPLS-connected devices – once it leaves the “MPLS Area” the labeling is stripped off. (Thus the reason ISPs use it internally to swiftly forward LOADS of traffic).
You CAN use it for a LAN-to-ISP connection, but given the nature of your traffic – which sounds mostly like data/web usage – MPLS would NOT be a cost-effective solution for y’all. A “regular” ethernet or – if you want to get fancy – fiber-optic link to your site would be a better, more cost-effective solution. (a 100 MBPS link should be more than adequate…)
Great Link for MPLS: NetworkWorld