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I've read a couple of reviews saying they can do 10 minute unguided subs
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I'd be very skeptical about that claim. My understanding is that while the harmonic drives are great for lack of backlash, they're notorious for large periodic error. In addition to that, going unguided at any reasonable imaging scale is about more than just having an accurate mount, you really need good modelling software as well. If you buy one of those expecting 10min unguided subs at a reasonable image scale I almost guarantee you'll be disappointed.
Huge disclaimer: I'm currently selling one of the mounts I'm about to talk about
but I'm also trying not to freight it, so this not a matter of me trying to sell my mount to you, it's my genuine experience/opinion.
I've used the following mounts of the years: CG5, EQ6(x2), EQ8, Avalon Linear, Astro-Physics Mach 1 GTO and a Mesu. Absolutely no question about it, the Mesu was the best of the lot for my purposes.
EQ8, EQ6 etc just weren't accurate enough for my liking... I was imaging at 0.5"/px at the end, and typical guide errors on mounts in that class are more like (total RMS) 0.6" on the best of nights to 1"
Avalon Linear did 0.5" total RMS on the best of nights as I recall, I think 0.6" was more typical, but it did have huge periodic error (e.g. 30") meaning you have to guide fast to overcome it.
Astro-Physics Mach 1 was a beautiful mount, I routinely got 0.5" total RMS, occasionally down to 0.4", however they also have some Dec backlash (I recall 200-300ms being standard) due to the gears in the drive system which actually did bother me... obviously way better than EQ6 class mounts all the same, but I did find that frustrating and I did not expect it when spending that kind of money. Honestly not sure how much it impacted my images, maybe not at all, and I seriously doubt people with more typical imaging scales would notice an issue, but my image scale was tight and I'm a perfectionist. The Mach 2 with absolute encoders would likely be a perfect portable imaging mount if the capacity is sufficient, which it would be for most people.
Mesu 200 has been a dream. It's huge and heavy so not good for portable people, but in an observatory it'a fantastic. Software isn't the most user-friendly, but it's very powerful once you get the hang of it. Absolutely zero backlash due to the friction drive, which I love. I'd sometimes see total RMS down in the area of 0.2" on this mount. I did find it quite sensitive to balance and simultaneously hard to balance which isn't a good combo, and the lack of through-the-mount cabling in the version I have means you have to be careful with your cable management, but in an observatory you get that stuff dialled in and leave it alone. The Mesu 200 is without a doubt the best mount I've used. The biggest thing I missed there was the lack of through-the-mount cabling, which lots of other mounts don't have anyway.