You're going to get everyone's personal preference, unless you can specify specific features you're looking for.
For examples:
Gas or electric?
Standard M4 or fancy M4?
Blowback (faux bolt movement)?
Recoil?
Empty mag stop fire?
Quick spring swap feature?
Etc
I'd personally recommend
against a PTW, at least not until you've had a chance to handle PTW, standard AEGs and GBB rifles.