I just went from a vantage ultra 2 channel, to a verus edge, which has 4 channel. There were a few times that I wished I had the 4 channel (checking can high and low simultaneously at one module, for example, uses all the channels on your 2 channel scope). At this moment I'm struggling to recall the specific examples that lead to me wanting more channels but in a professional capacity using the scope between 1 and 5 times a week, there were probably 3 times in a year I could have used the extra channels.
The Verus was used and with the trade in vantage was a good value.
I would also consider picoscope and VCDS if all you're doing is VAG, or pico and an OBD tool of your choice. The snap on really isn't a proper oscilloscope, it's quite slow. I have an interest in radios, for example, but the snap on isn't fast enough for that. I have struggled to scope flex ray with it, but according to snap on it is possible to do so - it could be error on my part.