Hmm, I actually got a Cisco from my ISP and ended up buying a Netgear as the Cisco was too unstable.
The Cisco is a Docsis cable modem with built in wifi router. If you use your own router you can have the modem set up in bridge mode, which I did. Ever since the connection is stable. You have to call the ISP to have the modem switch to bridge mode. Funny thing is when I did, the person on the phone agreed with me that using my own router would probably be a lot better.
I'm sure I could buy my own Docsis modem as well, but for me that thing is now part of the internet, not my home network. So it is in untrusted territory anyway. As long as it works it is fine.