If you plan on keeping the car, I'd go with a warranty.
My parents have a 2008 Focus (my old car). Great little car that keeps going and going...until recently. I drove it and noticed that it was taking a long time to shift gears. I checked the fluid and it was pink and at the right level. I figured that it was just a shift solenoid. I dropped the pan and noticed metal shavings. So, my dad took it to a local transmission shop where they put in a used transmission. The car had about 157k at that point. The install only came with a 90 day warranty. Fast forward 4-6 months, I was changing the oil and noticed that the transmission was leaking at the spot between the transmission and engine. I noticed that the original setup had RTV in this location whereas this does not. Long story short, stick with a place that has a good warranty.