Hi,
1. I got the version with the chain and derailleur. I figured the “tried and true” setup would be easier to work on and repair if necessary. (Granted, I’ve never had a belt-driven bike before, so I don’t know if this is actually true. But that was my reasoning.)
2. I’m not much of a “gravel” rider. I mean, there are some gravel sections of some of the nearby trails that I ride, but gravel performance per se wasn’t a priority for me. Also, I only rode on the original tires that came with the bike (Hardcase E6 Lite tires, I think; don’t have them in front of me right now) for a couple of weeks before swapping them out for Schwalbe Marathon E-Plus tires. Not because there was anything wrong with the stock original tires; there wasnt. I just preferred the Schwalbes from having used them on another bike (and they have much higher puncture protection).
3. I went with the 4s vs the 3 for several reasons, primarily as I recall: (a) I believe the 4s is very slightly lighter; (b) the 4s has a somewhat more powerful motor, which is helpful on steep hills; (3) the 4s is Class 3 (motor assist up to 28MPH) whereas the Verve 3 is Class 1 (motor assist only up to 20MPH). There were a couple other things - maybe the 4s has like an extra gear compared to the 3? - that I can’t remember right now.
I have the 4s step-thru version. I’ve been very pleased with it. The combination of it being step-thru and the fairly upright seating position mean that on days when my lower back is bothering me, I can be somewhat more upright rather than leaning far forward (and with the adjustable stem, you can position things to be *really* upright if/when you want); and on days when my right hip is bothering me, I don’t have to swing my leg way up and over the saddle. (To be clear, neither my back nor my hip are serious ailments, more annoyances. But I am in my early 50s and both can get aggravated in certain riding positions on certain days). The motor is more than powerful enough and fast enough for my purposes, and I feel very well “planted” while riding.
I did have the Trek store upgrade the Purion controller that comes standard with the 4s to the larger and more informative Nyon display. The Purion was fine - indeed, there’s something to be said for the simplicity of having just a controller as opposed to yet another screen - but I wanted the additional ride data that the Nyon can display and record (cadence, pedaling power, calorie estimates, etc). I don’t really use many of the other features, such as maps/navigation, mostly because I haven’t needed them enough to invest the time in figuring out how to use them.
Also: big shout-out to my local Trek store! Their service has been excellent: the longest I’ve ever had to wait for the bike to be serviced has been 3 days, and that’s just because I took it in on a holiday weekend. Most of the time, they promise 24 turnaround for routine matters. And contrary to my expectation of a big chain, the employees there to a person are friendly, knowledgeable, and happy to share advice and just chat bikes.