I tend to post that the bus sharing is a negative but then ALL WDW resorts have some sort of negative (size, sorry pool, location, old, whatever). I love POR. The only negative I see with it is that bus sharing thing. We stayed at POR in April of 2006. We shared busses most of the time during the day and several times during the night. It was only a problem once (our room was near the last stop) or twice when the bus couldn't pick us (and several others) up since it was too full. Another bus seemed to come along really quickly, so I am assuming the driver radioed and another one got sent pronto. In December of 2006 we stayed at FQ. That time was during Christmas week and we shared constantly with POR. There were many times (to Epcot and MK in particular) that the last two stops of POR couldn't be picked up. At that time, I was really glad we were at FQ.
In the end, it can be a problem. Is it a constant problem? I don't think so, there are too many people that love this resort and won't go anywhere else. I have just decided that next time I stay at POR I will rent a car if at all possible. If I can't rent a car, I'll still stay there and just walk to the main depot if it looks dicey. The great points of POR so outweigh the bad ones that to me its not a big issue, just an issue.
Just like CBR has the "too spread out issue", French Quarter has the too small slide issue, CSR has the convention issue and well you get the idea. Whether a resorts negative issues affect you just depends on luck and what is important to your overall stay. I think the main thing is that if you want to be someplace right on time (park opening, ADR) and you are at one of the last couple of stops at POR either allow some extra time or walk over to the first bus depot. Of course renting a car eliminates all worry with this problem!
I would never tell anyone not to stay there but when I post my replies regarding this resort I do generally mention the bus thing based on my stay there and at FQ. In the end, with a 1000 rooms of its own I think FQ is too much to tack onto POR's route. I see why they do it since by Disney standards 1000 rooms is a tiny resort but I still think the two resorts combined (they have over 3000 rooms total as compared to CBR's 2100 rooms total) are just too much for once bus route. Especially during peak times.