Ok the Zumo XT has a fantastic screen. Its great at playing spotify. The weather and rain radar functions are nice. The phone conectivity is great and the roundtrip and adventurous routing functions are probably good too though I've never used them. However, as a pure gps device capable of following a route created in basecamp or even as a point to point device it is sadly lacking and a Zumo 660 is certainly capable of doing a job as a gps even though the rest of the functions are missing. Don't get me wrong i'm persisting with the thing because I'm a masochist and hopefully Garmin can get it sorted out. However, I joined the Zumo forums because after months of use I noticed it was not doing what I expected (I hadn't bothered joining previously as all my other garmin GPS devices had worked as expected). Particularly in following routes created in basecamp and routing point to point using faster time. This was particularly noticable for me as I regularly run two satnav types the Zumo XT and a Zumo 390 and 340 (basically the same unit but the 390 has a telephony funtion). One day I headed out to the Fermangh, Leitrim, Sligo Donegal border. There is a mountainous area here near Lough Melvin with lots of senic features. I didn't route to the area but created a number of waypoints that i could visit point to point until I run out of time. At the last point I visited I routed for home just outside Manorhamilton and all of my units are set to route faster time. When I got to Blacklion on the border the Nav wanted to route me through Enniskillen which being built on an Island is a traffic jam

The nav wanted to route me through it but I decided to turn right and go through Florencecourt which i knew should take me over an Island on lough Erne near Carrybridge and out onto the main A4 road to Belfast. As I was heading towards Florencecourt the Nav told me there was a 15min delay in Enniskillen but offered no detour with the little detour button. I couldn't remember if I had to turn left or right at the end of the Florencecourt road so stopped and looked at the map

. The unit told me about the delay and continued to merrily route me towards it and continued to do so until I had crossed the Island in lough Erne (on minor roads) and then correctly directed me to the A4 and shortened the predicted arrival time by about 25 mins as the distance was shorter and the traffic was missed. Also on the return I consistently give me delay times on the route it calculated through Belfast. I live on the Eastern Burbs and dont need to go through it from that direction. The alternatives it was suggesting would have brought me into a lot of traffic. I ignored it and took more minor roads to reach home and it kept nagging me to ride into traffic. Confirming that faster time on the XT means faster roads. As an experiment I put a route from Florencecourt to home into all of the Navs at my disposal to see what way they routed. The results are interesting.
As you can see the only unit that wants to route me through the middle of Belfast is the Zumo XT this is clearly not the fastest route to my house from that location. There are slight variations in the other garmin units but are closer to what I'd actually do. This time the Zumo did not want to route me through Enniskillen but took me considerably further south and through an additional town to get to the A4. My conclusion on the Zumo XT so far is great infotainment unit. Great Sat Nav? Not so much. In places where you go off piste and just want to get quickly to your destination your phone and google maps would be best. I can use this on the TFT screen of my africa twin and it has the added bonus of voice commands which means you dont have to stand and prod the screen. Haven't found a decent app that works on Android Auto and takes the sort of routes I like following yet though.