In my experience, not really. I've gone from off-the-shelf routers (Linksys, D-Link, Netgear) to 3rd party firmware's (DD-WRT) and tried a couple Cisco devices (Pix Fw/Router, 800 series router, 1130 WAP) and none of the Cisco's were what I'd call plug and play. In fact, they usually start off with interfaces down, which is more secure but requires some fiddling. I eventually got PDM/SDM working on all of them but it required some CLI work and experimenting. In one cases, I had to downgrade my JVM to work with it as the installed version was not forward compatible (side rant: I really wish Cisco would learn some HTML/Javascript + whatever backend language like everyone else).
The good side is Cisco's documentation is very good, plus there are a lot of good tutorials you can find on the web. The hardware and software is rock solid; I've never had to reboot any of the 3 in months of uptime. Also, I prefer Cisco's IPsec VPN to the SSL VPN's (OpenVPN) on DD-WRT installs.