I have a like new Montana for sale.....works great but I am going to use my Zumo 396 LMT-S as the display is slightly brighter and easier to see for me. https://advrider.com/f/threads/ln-garmin-montana-610-gps-with-accessories.1463469/
Are there any programs that you can download into the Garmin 590LM to make it more trail friendly, I have one of them?
I use the have used the ZumoXT this year. When it works as intended*, it is really, really good. The screen is very responsive and bright (can truly be seen in any light), the maps, I believe, are based on OSM maps, tracks are easily shared to and from it wirelessly, it's waterproof, battery life is good, and it has all kinds of other nice bells and whistles (weather, track recorder, display of phone notification, music control, com connection, etc.). Before that I just used a Nuvi and it was really fine too. The nice thing was it was dirt cheap, so if I broke it, I could get a replacement for $20 on eBay. In fact, I kept cloned, redundant replacements on hand in case mine died, which never happened. *The XT has not been without its problems, for me and others. The first so many XTs shipped with loose mounts that caused a bad power connection, some had pins break out of the charge cord rendering the charging non-existent, and mine eventually just died, I think because the power supply was so intermittent, and was replaced under warranty. Because of COVID supply chain disruptions, etc., the warranty replacements were slow in coming at times. The new Montana 750 series also look really impressive.
You can get a Garmin 78 for around $200. It's an excellent GPS. The screen is smaller than the Montana and it doesn't have a touch screen, but it's a powerful unit.
Kyocera XD $40 Amazon flexible mount $14 locus map pro (or free) $9 you can get extra batteries for about $11 each on eBay/Amazon also here's the mega thread explaining everything https://advrider.com/f/threads/ultra-rugged-kyocera-phones-gps-smartphones-my-guide.1206076/page-253