Hi guys i'm just after opinions on IUI VS IVF

I just had my FS appt and i have servre Endo.. my FS said that i would need extensive surgery to get rid of it all etc and said after getting it all there would be a good chance of me falling preg naturally, but he is more interested in putting us into IUI or IVF then doing the surgery... he thinks we would have a good chance of falling preg as we already have one DD
He said the option is ours at the end of the day but he wants us to start with IUI as its cheaper etc.... As DP and i have been trying for over 3 years now we want to do what will give us the best chance... which we understand is IVF (we do have the form to start IUI but am wondering if we should be going to IVF instead)

So i guess my question is what made you pick either IUI or IVF??? (if you had a choice)
Do you think you made the right choice if you picked IUI before IVF???
How many goes did it take to get a BFP???
Other then the EPU and Embryo transfer how much is different between IUI and IVF???

TIA - I'm hoping someone can help... its really a how new world to us