Media for LAN-to-LAN with ASA55xx or routers

LAN-to-LAN with ASA55xx or routers

we're renting 100Mbit/s LAN-to-LAN connections from one sentral site to about 10 remote offices.

When upgrading the network equipment we can't decide if we should use:

1) routers (e.g. 2811) at the branch offices, and a larger router or an ASA5520 at the sentral site. or 2) ASA5510 at the branch offices and a larger (e.g. ASA5520) at the sentral site.

Will the 2811 have enough throughput to compete with the ASA?

Is 2) a wise choice or is it not neccessary to use ASAs in both end?

We don't need any advanced routing at our sites, and I understand that the ASAs wil do basic routing. Is that correct?

Thanks a lot for any answers!