I'm an advocate of medicated FET's...especially if you don't ovulate on your own.
We tried a natural FET and it was a complete disaster! According to OPK's we O'd, but 4 days after transfer, I got my period, so it was clearly inaccurate.

At least with a medicated FET, there is more control over your body, u/s are done to determine the thickness of your lining, which gives FS a better indication of when your body is ready for transfer - obviously the thicker the better!

My last cycle, I took Progynova from CD2, started progesterone pessaries 2 days before transfer (twice a day), we did achieve a BFP (but m/c). We'll definately be doing another medicated FET, I had success with that, so will stick with what I know. It is a lot more expensive with the pessaries, but I like that we had more control over what my body was doing.

Loula - am going to see my FS today for my 6 week follow up after m/c. One of the questions I have to ask him is about the quality of pessaries made from a chemist outside of the MIVF pharmacy. I've heard about a compounding chemist in Surrey Hills that make them for a fraction of the price. I just wasn't sure they'd be the same quality/product...you had no problems using them???