This ten pack is superb value when on usual offer for under £15 from Amazon - so stock up for the hols and Xmas (as a single cassette in a high-street shop can cost up to 5 times more than the unit price offered here). Quality and reliability seem perfectly fine for my budget Sony HC22E HandyCam, never a dropout and the picture is noticably better than with my old Hi8 tapes - I always record in SP though.
Note video tape such as used in these cassettes are proprietary 'lubricated' and sticking to the same brand of tape (e.g. these Sony ones) has been thought by many to reduce problems with the video head clogging up and miss-tracking. No-one seems to have reported problems mixing Sony MiniDV with Fuji, and manufacturers modified their dry lubricants back in 1997 just in case - but if you want to be really careful stick with one brand.
Incidently, MiniDV Hi8 standard8 video cassette tapes like these, and their recorded video images, have a projected life of 10 years after which even the plastic components of the cassette mechanism start to fail (besides will there be any miniDV camcorders to play these tapes in 20 years time). Over this period some of the signal on the tape will be lost slowly to noise by 'print-through' as the tape sits in contact with itself (by magnetic induction). This is particularly bad for older analogue tape (e.g. Hi8), but MiniDV isn't immune. Fast forward/rewinding the tape every year or so will help reduce this (as will recording the original in SP not LP). So transfer video tape to digital DVD before this becomes a problem, using the AV 'analogue in' on a DVD recorder works as well as a PC - and recopy your video DVD [with 'verify write' on] to a new DVD every 5 years [using a PC]. Keep the Sony tape master as well. Also look after your MiniDV camcorder, as tapes recorded on one don't always replay perfectly on another manufacturer's model. So think about archiving sometime or your precious memories might simply fade away.