Hi Mike,
I am happy to give you my thoughts, with the caveat that there are many others in this group that are better riders, know more about bikes, have more Rivs, etc. I do ride a lot, though, including 30 years of year-round commuting, until I retired 2 years ago.
I love my Homer! I think it's a great option for the type of riding you are talking about. I've been mostly on pavement with it and it feels fast and agile enough for me. The longest ride I have done was 56 miles (~4 hours, with a few stops), and that went well (I've done it 3 times). I had to verify that I was indeed slower than on my road bike because it didn't feel like it, but indeed I'm probably at least 1 mph slower. However, I have no back or neck stiffness even on long rides, which is amazing. Being in a comfortable, upright position solves a lot of problems. I know a lot of people in this group love drop handlebars, but after riding both drops and uprights I can't figure out why anyone would use drops who isn't in a race.
This weekend I rode Homer on some single track stuff along irrigation ditches we have in the neighborhoods down by the Rio Grande, and that went well. Fairly bumpy, with exposed tree roots, etc. No way I'd do that on my road bike. In getting Homer last October, I went for the "you pick the fun stuff" option, and was happy with that. I think the choices I made were handlebars (albatross), style of shifters (silver, end shifters because they look cool and i was curious), chain rings (42/28), 9 speed cassette. I wanted sidepull brakes because I'm used to dealing with those, but I think that's what they were going to recommend anyway. Unless I'm forgetting something, Riv chose the rest of the stuff and I have no complaints. I appreciate the amazing builds I've seen on here, but I was fine with whatever derailleurs and brakes the Riv guys chose, so long as they worked well...and they do! They put 48mm tires Soma Shikoro tires on which looked enormous when I first saw them compared to my 25 mm road bike tires, but they've been excellent. I gather that those are good but not top-notch tires, but they are by far the best ones I've had (I tend to be a cheapskate), and the ride on them is great. I added a Brooks B17 saddle and big MKS Grip Monarch Pedals (I can wear regular shoes!!!).
What I can't tell you much about is how Homer compares to other Riv models 'cause I live out in ABQ and you hardly ever see a Riv...except I can do a comparison with the Platypus, because I love my bike so much that I got a Riv for my wife, and the Platypus was the easy choice for her. And because she is 5'11'' we had to get the biggest Platy size (60), so I can ride that one, too (I am 6'1"). I find it surprisingly similar to the Homer. I'm not saying the same, but much closer than I would have guessed given the very different looking frame. They both feel long and stable, but the Platy feels equally agile, which I didn't expect. I have zero regrets, but if I had been able to ride both of them, I think it would have been a tough choice.
I can't comment at all on Sam, Joe, Atlantis, etc. If I had thought I'd do any bikepacking I might have considered one of those, but realistically that didn't seem likely and I just didn't see the point of getting a heavier frame, so Homer seemed like the sweet spot. And I didn't want to go with the Roadini (though BikesnobNYC seems to be in love with his) because I wanted to push away from thinking about weight and speed.
I hope this is in some way helpful to you. Attached is a picture from a few weeks ago of Homer and Platy out for a ride in the South Valley of ABQ. There's a nice donkey down there named Betsy that we liked to feed carrots to.
Best wishes,
Chris
P.S. I'm adding a "racing" wald basket in the back because I like my wife's so much. I never would have thought I'd have a bike with a kickstand and a basket, but it's happened.