Got Leather does nice work from what I have seen on here. If you choose him you should be in good hands. As far as price goes that's a tough one as it depends a lot on how long the work will take (condition of car, skill of detailer, severity of issues, etc.), what you are wanting out of the final product ( just fix the area with issues, make it shiny, correct the big defects only, show car finish, etc), and finally your location. I have no clue what detailers in DC get for their work. Expect to spend at least $150 for an exterior only detail. If you have major issues or are looking for a show car finish the price can go up as high as you can imagine for paint polishing alone.
Some questions to ask:
Are you insured? IMO it's not a deal breaker if they are not. Some very competent detailers don't have insurance. It's good to know one way or another though.
Do you have before and after pictures of your work? A resume is nice but a lot of detailers will probably direct you to internet write ups. Which are nice because it will give you an idea of their process and attention to detail.
Have you dealt with this type of issue before? The more experience somebody has at doing something (the CORRECT way) chances are the better they will be able to deal with the issue you have.
And finally, ask them what to expect from the finished product. They should have a good idea of what you will see or not see when they are done. Shot in the dark detailers or those that just do the same to every car regardless of condition are not you best option. A good paint polisher should be able to give you a general idea of what is possible with the budget you laid out and the current condition of your car. It might not be exact but it should be a good EDUCATED guess.