I've flown FR a couple of times years ago, before they started heaping on even more extra charges. Both return flights were on time and it was actually a pleasant experience....
However - They started messing about with the routes and schedules at PIK which meant some flights either left too early in the morning or arrived back too late at night. As it was impossible to get to or from PIK by public transport and given we only lived 15 minutes away from GLA that put paid to us using FR again.

Great to use if you get a bargain or want a direct flight but I would definitely pay the extra 'insurance' to fly BA for peace of mind and the extra schedules if anything goes wrong.