Me and my girlfriend booked a 3 day motorbike tour with QT. We were doubting whether to go with guides or not, and ended up going with guides. After seeing half the people who went without guides (some with previous biking experience) having some fall we are really glad we did this.
Our guides, Nô and Cừ were incredible:
-They have done these routes so many times, that they know the best view points. They had no problem stopping for views and pictures, and in fact genuinely seemed to enjoy showing off the beautiful scenery they have in Ha Giang.
-Where many other people had to get off their bikes and walk the way, they could ride along. At first it was a bit scary, but then you learn to trust them.
-On the personal level, they were incredibly friendly. We had great times with them, both during the trip and the night drinks and karaoke. But even once the trip was over, while waiting for our bus to Hanoi, and not having had dinner because of time constraints, Nô invited us to join the staff for dinner which was really nice (and I got to try silkworm pupae...).
As for the tour:
-Definitely the highlight of our 2 week trip to Vietnam (having been in Hanoi, Halong Bay, Ninh Bình, Da Nang and Hoi An).
-Everything really well organized and upfront. You pay once and they take care of you for the rest of the time.
-Some of the most beautiful scenery I've ever seen.