You obvious you do not understand much about computers & video. There is not a single manufacturer who will tell you that tape is a better storage media for video data. Right now, tape is used as a cheap archive media, not the best but the cheapest by a large margin. To archive a 60 min. tape requires at least three DVD's (saved at the same resolution as the tape.) I know, I know, three DVD's are much, much cheaper than tape. Except that someone has to record the video to the DVD's and labor IS expensive. And remember that the material is already on a tape that could be filed. So anyone maintaining a tape library does so because tape is their acquisition medium. Currently, high-end productions are transitioning from tape/film to digital storage media (blu-ray, solid state memory (P2 cards), hard drives and the like.)
Here's the low down on videotape. Stored properly, quality tapes will maintain signals for about ten years. Tapes must be stored on edge, in climate controlled conditions. Tapes should be retensioned (FF to end & RW) on a yearly basis. And even then, significant quality losses are not uncommon. The main problem is that the oxide coating loosens and falls off with your video. DVD's are rated (by simulated aging processes) as archival for around 100 years. But for both media choices, starting out with good quality, name-brand media insures the best long term results. And please do not forget that videotape is damaged by every pass through a machine. The more it is played, the more the signal is rubbed off. DVD's have no wear from playback.
Now let's discuss the reliability issue. Just peaking inside the "tape hole" of any VCR should tell you it is filled with all kinds of moving parts. Any engineer will tell you reliability decreases as the number of moving parts increases. Thinking a tape recorder does a better job than either the DVD, hard drive or solid state because it has been around longer makes no sense at all. In fact, reliability issues have a great deal to do with why DVD's, hard drives or solid state recordings are becoming popular. Tape is very fragile, if one trip in a deck goes awry, that video is permanently damaged. And it is in danger every time it plays back. So it should come as no surprise that other storage mediums are much more sturdy. But anything with moving parts will have problems when jarred or bounced. Tape cameras record extremely distorted video when jarred, but recording to computer media, most systems have buffers & checksums to insure all the data is properly recorded. Still, solid state systems are the most resistant to vibrations. No moving parts equates to most reliable.
Finally let me toss in my opinion/advice to the couple, albeit too late to matter. I expect you will be using the camera to record important family events, personal things. Image quality doesn't matter once you reach the limits of your viewing device. The standard DVD disc has done that. The video recorded on miniDV tape is quite a bit better in quality than our TV's display. (It is also quite a bit less than HD video quality.) The quality of the mini DVD's is also greater than our TV's display. Since our couple will be watching a TV, then image quality for archiving is functionally the same. So the real questions are how much editing do they really want to do? Do they plan on creating productions or videotaping events? Are they planning on cutting out the blurry or shaky bits, or is there a script determining the editing? Since they didn't ask about camera features, only format advice, they are not going to be producing programs. So basing arguments on image quality issues is just beating a dead horse.
After working directly with amateurs & video neophytes for 25 years, here's my advice. You have one simple decision to make. How much video do you need to record before going home? If you are planning on taking vacations and recording video for a couple of weeks before storing it in the computer, you'll need a format where storage is expandable. So I'd recommend the DVD camcorders because you can buy discs anywhere tourists frequent. However the best camcorder for the family video enthusiast are the hard drive recorders. You shoot to a hard drive, then hook it to your computer as you would any other external hard drive. Then you can transfer files for editing later, or edit from the camcorder and save it to the computer for burning a DVD. Once you have what you want on your computer (or your DVDvideo disc) the drive is erased and used again. So even if you are carrying a portable hard drive and/or laptop, when you have a great vacation, I guarantee you'll run out of memory. The real advantage to DVD & miniDV recorders is they store the video on removable media (that is always sold all over the world.)
I will say that the external memory problem already has a number of solutions and as the price of memory (hard drives & especially solid state, ie. SD memory cards) continues to drop, the best solution to the problems encountered by home video enthusiasts will be recording to a memory devices. As for HD video, home video is made MUCH, MUCH more difficult with any foray into HD. Until everyone you know either has or is considering getting an HDTV with a Blu-Ray or HDVD disc player, HDV is useless. Current equipment records & plays at a quality level limited by your television set. And don't forget, you can still watch your standard def videos on HDTV's. Keep it simple until you see the need to change.
Sorry I went on for so long. I just hate seeing factual errors passed off as truth. And making ridiculous claims even if you admit to having nothing to support them is rude, crude and needs to be pointed out. (By the way, I am an independent video professional. I use a variety of formats, depending on the job. Since I shoot mainly for cable distribution, I mainly use miniDV for the issues mentioned above.)