The MS250 can take a redundant power supply while the MS210/MS225 can only use an RPS (which is horrible - don't use RPS). So this might affect your decisions.   If all your routing is static then the MS210/MS225 option will be sufficient. The MS250 adds OSPF dyanmic routing.   The MS210 and MS225 can be stacked together.  They can not be stacked with an MS250.  An MS250 can only be stacked with another MS250. ... View more