Hi Thor,
I can see why you would be more confused after reading all of the posts here. There is a lot of misinformation posted in all kinds of forums by well meaning people, even some here. While everyone may have an opinion, not all opinions are equal. I would suggest to you that you understand the qualifications of the individual/s that you are taking advice from. With all forums, sometimes the person behind a screen name is giving advice about something that they don't really understand. They might even be some kind of middle age loser living in their mother's basement who gets a rush from giving advice to people. It reminds me of the old SNL sketch where Chris Farley plays a motivational speaker who is actually a loser living off the government and living in a van down by the river...lol... You can watch that here:
http://vodpod.com/watch/472139-living-in-a-van-down-by-the-river
I'm not pointing a finger at anyone in particular... just a generality. Hopefully everyone here has a high enough self esteem that they can just take my word for that. If not... well... don't listen to that guy...lol... The point is, be careful who you take advice from.
Now, your question is: what is the difference between polyaspartic and cycloaliphatic epoxy or other epoxy... Basically, what is difference in the chemistry of polymer flooring.
There are MANY types of epoxy materials. The epoxy cycloaliphatics will be on the upper edge of performance when compared to waterbornes, amidoamines, polyamides, or standard aliphatic epoxies. However, when I say that I am speaking in relativity. Each of those chemistries have different advantages. The cycloaliphatics in general are more resistant to yellowing. It becomes hard to generalize the chemisty because performance is so dependent on the actual formulation. In other words, a cycloaliphatic system might outperform a polyamide for abrasion resistance, but it wouldn't if the polyamide is modified ceramically. But, IN GENERAL, cycloaliphatic epoxies are the upper end for garage floor epoxies. *Better things exist... they are just generally outside of most people's budget for a garage floor.
Polyaspartics are a type of polyurea but just made with a diamine. Polyaspartics are difficult to formulate and there are a TON of bad formulations out there. They cure ultra quick and the problem is always trying to slow them down. Furthermore, water drives the reaction. The biggest problem that we have seen is from solvented polyaspartics. It's just a bad idea to put solvent in them. While it slows down the cure to make it easier to apply, it leaves a huge potential for the top to skin over (because it is curing faster due to moisture in the air) and then it traps the solvent in the coating. SO, it can leave you with solvent odor oozing out of your floor for months. It can make your house stink and can make you sick. There was a post about that on these forums about a year ago. Anyway, a good polyaspartic formulation will give you a durable floor that is resistant to yellowing. To date, we have not been able to commercialize a polyaspartic that we would feel is responsible to sell to a homeowner or other DIY application. It seems that every time we develop a more advanced idiot proof coating... THEY develop a more advanced idiot... lol. So, we developed a 90% solids hybrid urethane that gives you the surface benefits with a much easier application. It is much slower to cure though than a comparable polyaspartic. Many users have sung it's praises on these forums.
SO,
IF you are going to do it yourself, I would suggest a combination of products.
First, use a good 100% solids epoxy primer that is NOT moisture sensitive.
Second, use a good cycloalipahtic 100% solids epoxy body coat...
Last, topcoat with a High Performance ALIPAHTIC urethane.
My garage floor is similar to yours with about an 8-10" skirt outside of the garage door that I wanted to protect. So, I did my floor as I described above but stopped the decorative part of the coating at the garage door. I cut a groove in the concrete (a key) that is under the garage door when it is shut. It's not that hard to do. Then, when I topcoated my flakes with the EnduraShield 2254 urethane I continued that out past the garage door. So, it's got a nice clear protecting it.