I've used both the Copper Spur 1 and MSR Hubba; I chose the Hubba (and, eventually, replaced it with the Carbon Reflex 1.)
The Copper Spur is a very nice tent, and if you're not as picky about gear as I am, you'll like it a lot. (The fellow who got mine does.) You're right: it has more floor space than the Hubba or Carbon Reflex, and that space is probably a bit better arranged. (Though, in practice, I didn't find much meaningful difference - but I don't carry a lot of gear that needs stowed, either.) The CS1 is narrower at the foot and wider at the head, so you get a bit more room in the head and shoulder area to store gear; it's a bit harder to store a pack in the foot end, though. As far as weight, the CS1 is a bit lighter than the Hubba - but a bit heavier than the Carbon Reflex 1. The CS1 and Hubba are both freestanding; the Carbon Reflex 1 is not (though you can steal an idea from Tarptent and use your hiking poles to make it reasonably freestanding.) The CS1 is the bulkiest of the three tents to pack, followed (in order) by the Hubba and the Carbon Reflex 1.
All three tents are roomy, well-ventilated, lightweight, and easy to pitch. They're both stable in the wind, and will keep you dry. So, why did I prefer the Hubba?
First, the CS1 has a definite high(head) and low (foot) end - which means that if, like me, you occasionally end up with the head on the low end of the site, you have to turn it around - which may put the door in an inconvenient spot. With the Hubba, you just reverse the head and foot of your sleeping bag; since it's a symmetrical tent, it doesn't have a specific head and foot.
The door placement is affected by that design feature, too: the CS1's door is at the high end, with the result that you have to get in and scoot around a little to sit up; it also means that you can only open one side of the vestibule. With the Hubba, the door is dead center: you get in, and you're sitting in the middle; you simply lie down, and when you sit up, your sitting motion follows the shape of the tent, which puts you at the high point naturally. It also means that the Hubba uses a split vestibule: you can leave either side open, depending on wind or rain direction. The vestibule on both tents is adequately roomy to stow your boots, or a stove and pot, without interfering with access or egress.
The fly on both tents forms a small rear vestibule - it might hold some small gear - say, the stove and/or pot. The CS1 does score good points here - it has a small zippered access panel that lets you access this vestibule from inside the tent. Neither the Hubba nor the Carbon Reflex 1 has this nifty feature.
The deal-breaker, for me, with the CS1 was the door hinge: the door hinges on the bottom, which means the door falls onto the floor of the tent. You can roll it and tie it against the threshold, but I never found this to keep it completely out of the way - I was always concerned that I might tear the mesh getting in or out. (Are you getting the impression that I'm not at my graceful best entering and exiting a tent?) I far prefer the side-hinged door, like the Hubba/CR1 has.
Another thing I didn't like about the CS1 was the vent on the rainfly (the Hubba/CR1 does not have this.) I've always been paranoid about holes in my fly, and feel better not having that feature. I never had any significant problems with condensation in either tent, and it never mattered whether the CS1's roof vent was opened or closed. This isn't to say I've never had condensation (I have, in both tents) - but it's never caused any dripping or other issues in either tent, it's just been a minor amount I noticed on the inside of the fly in the morning. The large amounts of mesh in both tents seems to allow adequate breeze at floor level to keep things under control. Of course, this equates to "breezy" in cooler weather too; the CS1's nylon wall goes a few inches higher than the Hubba's, which helps a little - the extra height may also be why Big Agnes designed that roof vent, too.
I really can't fault the CS1; it would be my second choice - and it didn't miss by a whole lot being my first choice. I think it may be that I'm a bit fussier about gear details than most folks - and maybe not in a totally healthy way.
Either tent will work well.