Hey, remember that Wix Code is a beta product so it is reliable for a beta product. I have sites in production since october 2017 and one mega large since a month and they are working as they should.
But it is still important for you to undertand that Wix Code is a beta product which is clearly stated in the logo and on pages. Wix on the other hand is a super reliable product and we have sites since 6 years that just do not fail or crash.