Are more expensive parts worth it?
You can never judge a book by its cover - especially in electronics.

"Cheaper" parts sometimes work perfectly in an application. Sometimes they don't. Expensive parts may have just as many irregularities and variations as cheap ones - sometimes even nastier ones.

You can never trust any part in your design until you (1) fully quantify what parameters your design are sensitive to (2) fully qualify whichever parts you intend to use, and (3) come up with some contingencies when assumptions made in (1) and (2) fall apart.

Also, you can never really trust a datasheet 100% - it's never a substitute for proper validation. Many parameters in the datasheet are artificial, in that they're generally measured at 25°C at some test condition (voltage, current) that makes the part look favourable. I've seen 30-page datasheets and 3-page datasheets in my day. Can I say up front which is 'better'? Not always.

Whichever parts you use, make sure that the manufacturer has some field application engineering (FAE) people or a help contact so that if you do come across some weirdness, you may be able to get some assistance with mitigation.