Dan,
The 880 does voice recognition, but it doesn't do it as well as Windows Live Search (or the new
Google Maps voice beta on some BB devices).
According to Consumer Reports, the voice recognition in the 880 needs to be trained, and each piece said individually in prompts (what state? "New York" Where in NY? "Monsey" What street address? "455 Route 306"), since it is processing using the limited CPU power afforded by a mobile device. The guys testing it on their site shows how he constantly said "Ridgefield" yet the Nuvi persisted with "Fairfeild?". Yes, it HAS the feature. But its very "meh".
MS Live Search relies on a network connection and does server-side processing. In other words, it sends your recorded voice command to their powerful server farm which yeilds a remarkably accurate response in about 5 seconds (as long as there is decent network coverage) without any training at all. And, you can speak the place name conversationally (<beep> "455 Route 306, Monsey NY" <processing...done>) and it just works.
Its like comparing those call center voice recognition services (ala, JetBlue's service number) vs trying to voice dial a contact on your phone. There's no comparison to having a server farm process the voice.
Also, while the Nuvi may get traffic updates, street changes/updated maps must be purchased in sets whenever a new map pack comes out. Server-side mapping apps like Windows Live and Google Maps are updated regularly, and the latest maps are always available. Also nifty to use the Satellite map pic instead of just looking at vector lines of streets as you follow your blue arrow.
However, the server-side apps aren't perfect since they don't support text-to-speech (yet), and they rely on you having network coverage at the time... the last thing you want is to get lost out in the boonies where you don't even have cell service! That's why its good to have real client-side maps as well.
Also, some of the other client-side apps offer more graphically-intensive and easy to follow routing screens, with your choice of celebrity voices for shtick (Tom Tom) and best of all, you can find an interface that suits your taste instead of making yourself deal with the interface that comes with it (Garmin's interface is admittedly OK, but arguably not necessarily the best. A smartphone solution gives you the choice of interfaces).
The 880 may also support bluetooth dialing on your phone for the local search stuff I mentioned before, but its still not as well integrated or effortless as an all-in-one device. Searching by your contacts, saving a found local address into a contact, etc... sure you can do all that over BT, but it needs to be synced and your contact list transferred, etc...
I'd say the Nuvi 880 may do most of what I'm talking about, but only 50% as well.