Can't believe I haven't reviewed these yet. I've had 2 pairs of the Trail Glove 3 (blue pair, and grey/red pair in the photo), purchased via Zappos, since late March 2016. In warmer winter days in the Pacific NW here I wear them, and in the spring/summer/early-autumn days they rarely come off my feet. I also own a pair of Trail Glove 2 (green ones in the photo) that I've had since those were released (never had the original TG1) and I slightly prefer them, but only just barely. I wish that Merrell would release a shoe in this same vein that is just slightly insulated and with a gore-tex layer, this way I wouldn't have to *not* wear these in the winter months (like right now). They're just not warm enough. (Edit: I just discovered that they now do! - the Merrell "Parkway" and I just ordered it. Seems to be a TG4 with full leather upper!)
All that said - these shoes have held up fantastically. They are roughly the same size as the TG2 in terms of fit, but they *feel* larger due to the more rigid out-sole. The out-sole is definitely tougher and offers less ground-feel than the previous version, but in many ways that's not a bad thing - there's still enough to feel planted and connected, and when you're actually off-road and/or on trail, those many little rocks aren't as "pokey" as they were in the earlier shoe. Honestly I like haven't the choice between the two. My TG2s are still going great as well though I don't wear them as much simply because I don't *want* to wear them out. They've become a light-duty sneaker for me.
I also own a pair of All Out Fuse Trailer Running shoes by Merrel, which are similar but just nowhere near the toughness and connectedness that the TGs offer, as well as a slight drop and some cushioning. Since I already own three pairs of Trail Gloves I've resisted buying a pair of the new Trail Glove 4 and will likely wait for the next version and hope it's the perfect shoe since Merrell is getting closer and closer with this line.
I've had lots of shoes and the Trail Glove line is easily in my Top-3 of all the footwear I've ever had. Fantastic kicks and whats more - they helped alleviate my back pain and allow me to stand and walk for hours at a time. Yup. I dig'm.