(usr-tc) Ascend to 3com

We are in the process of merging two ISPs. Our ISP runs on the 3Com Hiper Arch Chassis the other ISP runs on Ascend. Since we both use ELI for our Channelized T-1s we are considering porting their dial in number over to our 3Com chassis at our location.. What problems should we anticipate moving customers from an ASCEND unit to 3com? Both are using the "V90 standard." protocol. Would we be better off using their ASCEND equipment? Any feedback is appreciated. Thanks -Brian