Hi @TheDaydreamBelievers, welcome. I'm also with GCRM, did 3 rounds of IUI before moving to IVF. None of the 3 worked. I have regular cycles and was using donor sperm, all cycles unmedicated due to no known issues. AMH 48 and antral follicle count 31 so all good numbers.
Yes IUI was attractive to us for the reasons 2mumlife mentioned, cheaper, quicker, less invasive. However it obviously didn't work for us.
Hindsight is a great thing and in hindsight I wish I would have gone straight to IVF. Obviously wouldn't be saying that if the IUI had worked! But the 3 IUI's took us about 5 months to get through them and then the wait after each for results, review letter consultation if you want it really drags things along!
Although IVF is much more invasive and costly, if you have good numbers and age in your side, you might only ever need to do one collection to get a few embryos for transfer. If you are hoping to have more than 1 child through this process then IVF has the benefits again of possibility of multiple embryos that you can freeze and transfer in the future.
Such a personal decision though and depends on a lot of things such as how quickly you're looking to move things along, funded or self funded etc. We are completely self funded and spent in excess of £6k to do the IUI's (including donor sperm) which never amounted to anything, hence my hindisht comment of it would have been cheaper and quicker had we just went straight to IVF.