We are 4 adults arrving at Sabiha Gocken airport at 8pm and going to Satir Sokak, Fatih. Hotel is offering 55 euro ride for all four of us. now there are three choices. Should we accept this offer or get an uber or get a taxi from outside? There are plus and minus points to get hotel transfer. Plus point is we'll be dropped exactly in front of hotel but minus is we have to go out straight away to arrivals. Getting a sim card or buying a travel card from airport will not be possible as driver is waiting for us. Is Uber a good choice and easily accessible as I assume there would be a specific pick up point for uber which we have to search for or should we just get a taxi? which is the cheapest option?

For 4 people, the 55 euro hotel transfer is a great choice. While a standard taxi costs around 40-45 euro, it won't fit 4 adults and luggage, so you would need a larger van taxi that ends up costing the same as the hotel's offer anyway.

Public options like the Havabüs shuttle are cheaper at 20 euro, but they only drop you in Taksim. Dragging bags from there to Fatih is a major hassle. Uber is also unreliable in Istanbul because it just calls regular taxis, which often leads to haggling over tolls or traffic.

I suggest using Transfeero for a private van at a fixed price. It ensures you all fit comfortably without hidden costs, and the driver is usually happy to wait while you get a SIM card.
I have used Transfeero for private transfer in the past for this exact reason. Instead of squeezing into a small taxi or dragging bags through the shuttle station, Transfeero gives you a private van for a fixed price. It is the most reliable way to ensure all 4 of you fit comfortably without hidden costs, and the driver will wait while you get a SIM card if you ask.