tbh I probably flat his flop bet and re-assess the turn...when he leads it can mean a number of things imo:
1. probe bet to see how good his Qx or under pair is
2. combo straight/flush draw trying to get a cheap turn
3. or strong made hand like a set hoping for your re-raise
there aren't too many scare cards that can come that would make your hand second best
once he's 4 bet shoved the flop it's either a flush draw or set for me but more likely to be a set due to you having the

their comments about you 3 betting pre flop shows that they have been paying attention to how you've been playing (very conservative by the sounds of it) knowing this, you could be the target of a bluff thinking that they can get you to fold a strong hand like

,

or

type of hand
for me this is a close one and I'm a feel type of player so would have had to be involved to have any inclination of where I was in the hand
I may fold as I have lots of chips left and plenty of play.....how did the hand play out?
let me know what you think?