Question re transferring a 2017 Premier Lease

I have a 2017 black Premier with 13,500 miles. Lease is 15k miles per year and was started on Sept 24, 2016 (therefore 2 years remaining) and the payment is $490 per month. Never had any issues with the car and has been dealer maintained. Actually it's the best car I have ever owned, but has always been a placeholder for the Tesla M3 which is now expected between November and January.

Does anyone have any experience with any of the 3rd party lease transfer sites? any other advice / experience to share?

PS - please no flames. Again, the Volt is amazing but intent was always to be a gap car... never thought Elon would actually hit his production targets.

charlotte, nc