I have never had an issue with my Galaxy S3 or S4. Frankly 9 times out of 10, it's the user, they have installed something, rooted it and don't know what they are doing, etc...
This is common not just with Samsung but any phone brand. Provider also makes a huge difference...For example I am with Telus in Canada, when 4.2.2 came out we had
no issues what so ever. Yet you see people on Verizon going nuts with crazy issues. There are way too many variables to blame the manufacture as a whole.
As for fragile screens. They are a glass screen, sure it's Gorilla Glass, but they can still break. It's like a window in your home, sure it's sturdy, until a rock get's thrown through it.
As an owner, you protect your phone, get a good case. They do break, and they can't take a lot of abuse.
As for eating MicroSD cards. Never had that issue, and don't know anyone personally that has.
I will take a Samsung over an iPhone any day though I will say that