On sale, they both look like they give great value. Both seem to be very well reviewed. The Hornet is a little lighter. the REI is a little cheaper and slightly better ventilation, but I'm wondering if I might want a little more material on the bottom for splash protection.
Anything about these two tents that would make one more desirable than the other?
For the SE, I'd still go with the REI. If it's raining, you'll have the fly on and you'll be wanting as much breeze blowing through as possible. I've never been all that concerned with splashing. I've generally found the fly does a good job. Now, if you camp on sand, go with the higher walls, as sometimes the blowing sand is problematic. The higher walls also give a bit more privacy for changing clothes, if others are around and you don't have the fly up. My vote: The Rei one.
FDR: “I ask you to judge me by the enemies I have made.”
I've never used the Quarterdome, but I have a Hornet 2 as my primary tent. The version I have is the prior model to the one you're looking at.
I've been very happy with the Nemo so far. My trips are primarily Florida, Alabama and Tennessee. You very definitely want the 2-person version of the Nemo for a solo tent. If you're looking at putting another person in there with you, make sure the person is a romantic interest. On nights with no rain and it's not too cold, I sleep with both vestibules open. It's done well with condensation all closed up though--no drip issues. I've had it in some moderate wind, and it held up fine. In the few hard storms I've been in, it performed well. It's quick and easy to set up---so easy that they don't bother giving you directions. Packed size and weight are fantastic.
I'm 6 feet tall and 205 lbs and it fits me perfectly with a little room on the sides of my Klymit Static V pad for bits of gear I want accessible in the tent. Definitely couldn't get the whole pack in comfortably though. I leave the pack in a contractor bag outside one of the doors.
One issue I've had is that I had to replace the shock cord in the poles after a relatively low number of trips. Zippers are really small and like to catch the fly if it's dangling, so I've been careful with it. Other than that, it's performed really well.
Looking at the quarter dome, I'm digging the high walls, but this Nemo looks like its walls are a little higher than the older version I have. And I'd figure the lower fabric on the walls on the quarter dome to be a plus instead of a minus, but I don't do a lot of trips in the rain. Looks like the quarter dome has bigger doors. My Nemo doors are fine, but bigger doors would be a plus.
I think this is one of those times where there isn't a wrong answer. You've narrowed down to two very good options, and they're very similar. I didn't realize how similar they are, and if something ever happened to my Nemo and I needed a new tent, I'd likely end up at the same crossroads you've reached.
I have some experience with the Quarter Dome. I found it a touch finicky in set up...read that as I didn't know what I was doing and had to mess with it twice in the yard before I had it right. Once I had the setup right, I thought it was a pretty solid tent. I think you will find the Nemo packs down a bit more.