[Blind-sysadmins] Recommendations for PBX and softphones for windows?

Hi all, We are, as i said in another thread, changing our PBX from a hardware device to a cloud/software based solution. Which PBX are you recommending? I saw that some are using FreePBX and FusionPBX. And which softphones are you recommending for Windows? We are also getting ried of our old hardware phones as well. I want something i can use comfortably which isn't in the way all the time when the phone starts ringing. Are there also headset recommendations? Our city has around 100-200 phones. Greetings, Simon