So late 2014 i have stopped using IPB, now i use discourse.
 
	Pros: 
	- FREE & OPEN SOURCE | Thanks for reminding me Phun :P - So no need to null it 
	- Looks beautiful than traditional forums 
	- Functions magically (no need to reload browser all real time)  
	- Better performance/faster than traditional forum 
	- Really responsive from get to go 
	Also more ->  http://www.discourse.org/about/
 
	Cons: 
	- You cannot delete a post permanently 
	- Discourse don't have full functionality of a forum software yet 
	- You have to know about a little about how ruby in rails works + postgresql (almost like mysql but better)  
	- Last of all, Hardware compatibility..... I could install IPB in any VPS/Dedicated servers (no openvz/kvm restriction/ no ram restriction) but Discourse needs at least (1 gb ram with swap- no matters to me) but KVM support with higher kernel version... The thing is almost all of the servers i own is openvz and KVM is rare almost but well nowadays with DO you can get one for cheap but this is where i got stuck and frustrated..
 
	So i would like you guys to compare Discourse with IPB, 
	Discourse official website - http://www.discourse.org/ 
	Their sandbox - http://try.discourse.org/