Depends.
If you need redundancy, then you need redundancy (if that's what your looking for)
For load-balancing, it is kinda worthless in a home environment, and would tend to mess things up.
I havn't seen a working multi-link solution in place, however, that would almost double your internet connection (also by using multi-linking).
By my understanding, there are two types of multi-linking routers:
1. It actually "combines" the connections to give you almost double the bandwith
2. It load-balances between the connections
#1 only works when it's two of the same type (ie: cable + cable from the same provider)
So in your solution it will load-balance between them.
Load balancing means "every other request is sent out the other connection". This is good for normal websurfing, as it splits the load over two connections. However, online gaming may mess up (if it begins a new connection, it will come from another IP address), it may also mess with FTP sessions, and especially peer to peer programs, incl. ICQ.