re routing

I have the 350 (and had the c530), so I am talking only from experience of those models. But there is no re-route per se. Rather it has the ability to recalculate the route if you go astray. You also have the ability to detour which offers an alternate route. You can keep touching that to get different routes.

On my Nuvi 350 it appears to offer just two routes, but I suppose that may change depending on your settings of roads to avoid. But it seems to offer the Faster route first and then the shorter route second and after that, cycles over...

so if I hit detour it will keep giving me new routes?

That seems to be the way my Nuvi 350 works. I've only had it a week but on one trip I went off route and the recalculated route wasn't any good so I just hit detour until I found one I liked.

Yeap, that is the way it works for me

Yes this is how it works on my nuvi 360.

Keep in mind though that if you are stuck on an interstate, it may take you several miles along your current route before the next exit comes up for you to take the detour.

I can second the comment about about being on interstate. I have a nuvi 370 and ran into a large accident on I-49 in Louisiana. Did a detour and it gave me a good alternate, but that was closed to local traffic since it was under repair. Another detour, took me back to my old route. No matter how many detours, my nuvi 370 kept giving me the same route back through the accident. All the routes that I thought would work were through Lousisiana local state highways. There is a connection between routing, detouring and rerouting based on the setting of "route preference". I haven't got it quite figured out yet. But having faster time set and being on an isolated interstate can, I think, affects detouring.

That is when you travel in the "third" lane. Which I only do if the exit is within site.