Hi Michael,
Apparently, I have the same situation. Need to change 1841's across the Country, for a Bank. I have been consulting Tech pals, and they suggest the SRX series for the same. i.e WAN routers.
As such.
SRX100
SRX210 etc etc to replace the ISR'x. I would be compring the capcity here, number of interfaces and licensing too. WAN capability is very vital too.
For the VXR, I have no idea.
Thanks.