Yes, I've had lengthy delay before out of IAD to transit IST for Europe (but found out that $2000 round trip J tickets have a downside...). Would cause me to definitely misconnect in Istanbul, and there were nonstops on United (same alliance) to my final destination and they told me to wait until Istanbul to investigate options. (Yeah, I should have just flown United in the first place - like I ended up doing on my own miles that trip - but I had booked a couple days in Istanbul on my return, which TK is generous in allowing and on one night forced layovers due to schedule will put you in a hotel or take you on a tour of the city).

The catering... I know everyone seems to love it. I guess it's the novelty of a chef in a floppy hat on board and use of nice presentation and trolleys. But if you think you're halfway sick of seeing short ribs on Delta... just wait until you become acquainted with "Seafood Potpourri" or "Rigatoni in Tomato Sauce" on TK. Nothing like flying them four long haul segments in one trip and having the exact same menu on all four flights.

Crews are nice enough. Probably less English than you'd find on European carriers. They are the only airline where I've had trouble connecting to wifi and the flight attendant took the phone from my hands and did some sort of back-door IP address entry to the onboard server to connect me. I've also found they do stick to their routine more often than not. When they've decided it's time for the cabin to sleep, you will sleep, and you will see the crew again when they put the lights on (and like a coordinated show are already standing in the dark at the end of each aisle with a tray of juice). Only really has been bothersome on westbound flights... when I am leaving IST at 4pm and getting into the US at 7pm, I don't want to sleep for 6 hours, despite the best efforts of the crew. "I make the bed now, you will sleep?"