Do any of you have any experience with SDXC memory cards?

So I have been saving money and got enough together and bought a Macbook Pro 13". I'm officially an Apple Sheeple now. But that's for another topic. For now, this computer is great and it has a slot for an SDXC memory card. I saw a 256GB on Newegg for about $100. Are these cards reliable though? Have any of you seen a case where one failed and lost all the data? I want to get one because I think it would be cool to store my data on it instead of doing Box. Just tired of logging in, etc. But I'm afraid that if I commit to this card, then it's going to fail. I will back it up of course but this is more about me not trusting the reliability of these things.