I have to agree with quest_for_silence. I have a P180 and an a Fractal Design R4, which is an older version. AFAIK the R5
has better front cover (R4 has one that was just as bad as the original from the P180), removable 5.25" bay, better filters and a "reversible" front door that feels flimsy according to some. The R5's new side-panels feel even more flimsy, wobble(!), but close easier. It also has a dedicated HDD LED finally. Oh and it has a new fan controller that you might or might not use.
My observations on the R4
- provides more potential airflow
- all fan slots are 140mm, but can fit 120mm fans as well
- the stock 140mm fans are not that bad, though the 140mm fans in general can be louder unfortunately last time I checked
- has much less problem with giant video cards (though you still have to remove the middle HDD cage to fit one that is over 310mm, leaving you with only 3 3.5" slots)
- cable management is markedly better
- dedicated ssd trays behind the motherboard
- USB 3.0 ports
- watercooling support, with basically all fan monts doubling as radiator mounting slots and more.
- the side-panel dampening is worse,
- the side panels are much more fiddly and can be prone to vibration
- the much softer gromets of the P180 are better at cancelling out vibration from multiple HDDs
- the P180 dust filters are much, much
better at blocking out dust
TBH, I was compelled to search eBay for another P180/1/2/3, (as none of them are sold here) due to the door vibration issue that came up every week to every odd month. It can be solved with a swift kick, but after years of searching for the exact cause, I could never find it. I do have to say though that a few friends also bought the R4, and none of them had this particular problem, so YMMV.