I've purchased several cases because I've purchased several P2V's and P2V+ for friends. They all have pros and cons.
Tradecraft specific P2V+ (new foam insert)
HPRC 2700WPHA2 Hard Case for DJI Phantom 2
The GPC Vision Backpack- Limited Edition (gopro case)
HPRC is a monster. Not P2v+ specific, but still perfect. Heaviest case. Best protection. Probably more than ever necessary. Bird fits perfectly and is very protected. More storage than other cases, but less specific storage cutouts for batteries. Very high quality. Do not think that it will fit in any overhead compartments.
GPC Backpack is the lightest, smallest and most convenient. Plenty of storage. Least protection because top is soft. Should fit in overhead bins. Easy to carry and very practical. Very good quality backpack. Not suitable to travel as checked luggage. I think it's a good second case when traveling locally.
Tradecraft is my favorite. Best balance of convenience and protection. Fits in Jet Blue overhead storage. Protection is more than adequate. My case fell out of a moving truck with no damage to bird. Case was scuffed up. Don't feel comfortable storing with props long term. Much narrower and lighter than HPRC. Lesser quality than HRPC, but still excellent. Less accessory storage than HRPC and GPC.
The other popular case which I never purchased is the gopro hard case equivalent of the backpack. The insert is similar and is also lighter than the HPRC.
If I was limited to one case, it would be the tradecraft.