I purchased an end-of-year 2024 Spyder from iMotorsports.com, after reading a few positive remarks on this forum. My first Spyder purchase too, and my experience was a good one. As for what your concerns should be, that sort of depends on what's important to you - for me, it was a matter of just thinking of every question I could think of. The salesperson on the other end of the line (Mike Kaye) was great, as was everyone else I dealt with, and their website and reviews were solid, so I reached a comfort level.
There were a couple of extra elements I had to figure out (wire transfer from my bank to theirs, and an out-of-state title), but they were helpful, and the transaction and DMV business went pretty smoothly. The bike was sort of dirty when it arrived (having been shuffled on and off the enclosed trailer as other bikes were delivered across the country, and there had been some weather too, apparently), but it came fully set up per the full BRP checklist, including alignment, and I found no issues with the bike whatsoever once I cleaned it up.
Anyway, not trying to make an advertisement out of this - no affiliation here - but just to say, I found it a good option for me. Good luck!