Overall very happy with my Roam.
Chose it over the Bolt because of the screen being bigger & colour. Colour screen is nice on the map and useful with the Varia (the stripe is green prange or red). Usually I’m riding routes that were pre-planned using Komoot so no real advantage there. A couple of times I’ve come across unexpected road closures and found the on-the fly auto-rerouting on the Roam useful. Not sure if the Bolt does that?
Have to say my Roam has a habit of dropping the GPS signal under light tree cover which is less than impressive - don’t recall my old Garmin Etrex ever doing that.
If I was buying again now I would definately look at the Hammerhead but my feeeling is I would still settle on the Roam because I find the display very easy to read in any and all lighting conditions. I also like the way you can “zoom” on data screens to see more or less fields (can’t remember what the feature is called), but perhaps Garmin & Hammerhead have that too?