Since I don’t know the specific answer to your question I’ll provide some input on the quality of the 3 brands.
Having owned multiple eskimos, clams, and a frabill hub as well as two Otter flipovers, I would hazard a guess that they are first and foremost all very acceptable. If I had to rank them for fit and finish I’d say 1) Otter 2) Eskimo and 3) clam with eskimo probably being best quality to price ratio.
Sorry I’m not so sure on which stores have them set up. I really like my eskimo insulated hub, I forget the model it’s one size smaller than the 949i, clocking in about 7′ x 7′ and roughly 35 lbs. I got it for a very good price, If I were buying new I’d go eskimo 949i for a hub and Otter for any sort of 2 or more person flipover.
I will say I’ve been eyeballing the clam kenai pro for a one man flipover for at least 3 seasons now but I truly have no need for it so haven’t decided to open my wallet for one. The “true flipover” aspect gets me interested, no poles to extend and you really can be set up in a minute. The Otter sleds are amazing but have trouble fitting under some tonneau covers, if that matters to you.
And finally I do think Frabill has some really great features but from the one hub I owned to the many handfuls of flipovers I shopped in the past the frabill brand consistently has notably worse fit and finish. But they come at a good price. I have no idea how their customer service clocks in compared to the rest.
I have only dealt with otter customer service and they were great. I did not have problems but they offered some new brackets entirely free to allow the sled to fit under a tonneau cover, so big points for free parts in my book. Unfortunately it still doesn’t quite fit under a bak revolver X4 since that is a very flush cover. I think my real ice fishing dream is a topper but cost is very much a factor there.
Hopefully you can get some more input here just in case you are not able to get out and physically shop the shacks before buying. Good luck!
P.S. with hubs there’s basically no reason these days to not go insulated. They are so light and compact, I firmly believe uninsulated would only disappoint in the long run regardless of brand.