Hi,
I would say that you can form an opinion on an airline from one flight.
However, please be aware that you could have a bad flight on any airline
For example I have had baggage delayed for two days on both Bmi/BA on the LHR-EDI which has given me cause to moan about both of them sometimes ( I have also been dealyed on both airlines but that is a price of air travel).
[ I did get 2k miles from BA for the luggage a month after it was delivered ( second time in a month that my luggage was delayed for 2 days]
Hope you havea good flight.
Regards
TBS