Hi, I've a Touch Pro on Vodafone UK flashed with ROMeOS² Italian Rom (just to let you know
). I'm using on it the headset controller that i had with my previous phone, an O2 Stellar (Tytn2) and a Sennheiser CX300. Absolutely no problem, and the sound looking great!
Now on your other questions.FM Radio is not working without headset, so you have to put them in the plug, and then FM Radio program will start. Otherwise, if for you is a problem having headset inserted in the phone, you can buy an headset controller (on ebay have a really low price!).
About the headset quality, I had before of Touch Pro, a tytn and a tytn2, and can confirm that the quality is the same, so I never used those!
PS: sorry for my english, I hope you undertand what I'm saying!
No time for losers!