I'm trying to determine whether there is any real difference among these. This topic has been done before, but I couldn't find the specific info I want.

Q:
Does the tape grade actually make a difference in wear on or reliability of the cam, or make 80min tapes less likely to break? Panny claims MQ, AMQ and XJ reduce wear (compared to what?). They are also said to hold up to more rewinding and age.

Considerations: A dropped frame or 2 per tape is not a big deal, but a broken or jammed tape is more than two dollar's worth of annoyance. I keep most tapes as backup (good thing, as the external HD I've been using for backup just died). They don't always get the best storage conditions (they may be in a self storage unit, or a non-air conditioned space). I will use some 80 min tapes (6.3mil vs 7) and don't want to deal with broken tape. Finally I wonder if the top grades can be replayed/recorded more. I've seen comments to the effect that dv tape can be used only a handful of times.

The mfrs know that the data recorded is far more costly than the tape, so they will automatically have sales of a premium tape based on 'feel-good', even if it's the same tape in a fancier box. To confound further, the price is nearly the same (B&H) for 'consumer' vs 'pro' grades. 80m PQ + MQ are both 6.25, with 63min PQ at 3.65. 'Consumer' 80min costs a few cents more than 'pro' 80 AY-DVM60EJ= 6.79.

Lots of decks EAT 80 minute tapes.
My advice is to avoid them at all cost!

I lke the AY-DVM63PQs as we have used hundreds in
our studio and very few drop outs.
I have also had good luck with
them recording HDV on my Canon H1. I used to like
Sony, but have had big drop outs even on their Digital MASTER
quality tapes.

As always, WMMV!

Thanks for the caution, I'm going to hold off using them. The 80 min are Pana MQ (the letters "MQ" make the tape immune to jamming, right? :-| ) and would only be used in the cam. I'd rather not have to fish broken/jammed tape out of the camera.
The thickness is only 10% different between std and 80m (7 vs 6.35mil) which is why I had hoped it would work. At B&H, the cam salesman held that an 80m would be OK if each tape were used <5 time, but the tape counter help said they've heard no good reports on it.

I concur with Jacques; because the 83 minute tapes are physically thinner there is more risk of drop outs or tape jams. However, people do use the thinner 83 minute tapes and usually don't have a problem. Depends on the needs.

Although I also advise against the thinner tapes and normally use 63 minute AMQ's to minimize the risk of problems, I recently got asked on short notice to tape a playoff game for my hockey league. Not being able to say no to a challenge, I played one-man band and ran three cameras. I knew from experience that the total running time of the game would be about 70 minutes and intermissions are too short to run around and change tapes on three cameras. So I stopped at Fry's on the way over to the rink and picked up the only two 80 minute consumer Panny tapes they had on the shelf (whew!) for two of the cameras and let 'em rip while I planted myself behind the centerline camera and changed out AMQ's between periods. End result? No jams, no drop outs. Would I make a habit out of using the 80 minute tape now? Still, no. But they filled a need.

I've been using the 80 minute Panasonic tapes for over a year now and haven't had any problem at all so far.