I bought and sold a 10' mission only because new sled out grew trailer. Haven't researched new to see if there is a price difference. I've heard mission construction is panelized (roof, sidewalls, rearwall etc) screwed together versus full welded frames. Its worth a question to your dealer. I wouldn't shy away from a mission.
From the rumor mill: Mission owner used to work for snopro. He left the company with a mission in mind, hence the name and one could say a successful mission.
Since the guy who owns Snopro lives in my town and started his business here I'll suggest you go Snopro.
Seriously, both are good. My father has a Snopro 12' enclosed and he also looked at a Mission. The Snopro seemed to have a bit better fit and finish so that's what he bought. It's a really nice trailer.
The fellow who owns Mission was a SP employee. I'm 90% he left when SP sold out to Thule. The original owner bough them back a couple of years ago though so they're once again a Maine made, Maine owned business.
I don't think you can go wrong either way. I have an older SP cap on a Triton trailer that I bought used this year. Seems like a nice cap, I just wish the PO took a hose to the whole rig at least once while he owned it...
i,m also looking into a clamshell type or crossover mission or snopro i had a 2002 snopro cap on a karavan trailer it was great but the cap had issues with the roof atachment bars the sides are welded together like a wall in youre house so is the roof the problem is when they attached them together they used aluminum tubing and screwed everything together problem is when you get weight on the roof(snow) the roof will flex and pop goes the screws now mine did this before i bought it so i removed the old screws and used larger ones where the front screws into the roof but the holes keyholed (oval) so now i needed even bigger screws to makeup the difference it did hold up for the 2years i had it and heavy ice sinse then they stopped doing it this way and use sheats of diamond plate aluminum on all attachment points looks nice so they improved on the design but sledd dock is fully welded no screws and also maine built and eztop same design different location (northwood nh) mission, snopro, and highcountry all are same exact trailer (different decal)i,m looking at a Mission crossover they have a video on you tube