Do NOT waste your money flying business class, not with Turkish Airlines. They go through great lengths to make a mockery of business passengers, at every point in the journey.
First, during the boarding, whether they are boarding through a connected jetway or through buses on the tarmac, they invite all passengers to board TOGETHER (against any travel etiquette for business passengers by any other airline). Their boarding is equivalent to sheep being taken to pasture. You end up queuing behind coach class passengers (and lots of them). If it's your lucky day (NOT), by the time you get to the plane, some coach passengers may have stuffed their bags in the overhead bins of the business cabins, and you have to juggle to find some space.
Oh, the chairs don't really recline, and there is no leg rest. (in BUSINESS CLASS). I thought my chair was broken until the flight attendant came and told me that they were all like that.
Second, during the flight, very often you get up to go to the bathroom, to find that some babushka (not sure of the spelling) from the coach cabin is using the business class lavatory and could be there for the next 20 minutes. That's OK.
Upon arrival. Many coach passengers rush through the business cabin and come to stand at the front door ahead of the business class passengers, this under the passive watch of the crew who does nothing to stop them. Then, when you get to the tarmac, there are several buses, one of which is for business class passengers. But the coach passengers are already in that bus (which is smaller); so real business passengers when they arrive on the tarmac are told to proceed to the general bus where they'll have to wait for maybe another 40 passengers to fill that bus before it can go to the terminal. That's what happened to me.
Last, your checked bags (even with the priority tag) will arrive amongst the last. You will watch coach passengers grab their bags from the carousel and leave, while you and other fellow business passengers are waiting. At some point, I thought maybe there was another carousel where business passengers' bags were rolling (KLM does that in some countries). , I think Turkish Airlines go through great lengths to make sure your experience as a business traveler is anything but. They really do everything to piss you off, in case you weren't already during the boarding.
Please don't waste your money flying Turkish business class, unless you want to know how cattle or sheep feel when they are being led to pasture. The boarding process of Turkish Airlines will sure give you a "first class" seat (pun intended) in that experience.