This has been my experience as well. My iPad 2 was extremely stable but the Air crashes maybe four times per day, if not more. I only have 16gb and virtually no space remaining so I'm hoping that's the reason for the frequent crashes.
I'm returning the Air if my Mini Retina is relatively flawless, otherwise it's a LTE 32gb Air for me, and at that point frequent crashes would be a bummer.
I had an iPad 2 that crashed all the time. Low memory jettisons. So I upgraded to a 3 hoping the 1g RAM would fix the issue. But it crashed a lot. Not as much as the 2 but still a lot. I was very worried when the iPad Air came out with only 1 g of RAM but decided to try it and figuring I would return it if it still crashed.
So far the Air has been great about not crashing. Only have seen 1. But the Safari tab reloads are annoying. There has to be a memory leak in Safari. But if there is then it's been there long enough for Apple to have addressed the issue.
While I really like my Air I'm thinking this may be my last Apple product until they deal with the memory issues. When the iPads first came out they were the only choice if you appreciated the form factor. But now there are other choices. Each has a trade-off. I have a lot of $$$ invested in the Apple ecosystem but I'm ready to ditch it all if they don't fix the issue. Sigh...