The Magnavox would pretty much be an exact replacement for the Toshibas you have been using. They come from the same factory with very similar operational interface. The only real difference is the Magnavox 533, 535 and 537 models include a HDD recorder along with the DVD section.
However, just because the Magnavox includes an HDD like your DirecTV PVR does not mean it has anything remotely like the capabilities of the DirecTV PVR. Like your previous Toshiba DVD recorders, the Magnavox would simply be a standalone accessory that lets you offload recordings from DirectTV by copying from the PVR to the DVD recorder. About the only advantage you get by choosing the Magnavox over another Toshiba is the Magnavox HDD lets you offload from the DirecTV PVR in much larger unattended chunks (several hours at a time) and then burn the DVDs later when it may be more convenient.
The "replaceable burner" in the Magnavox does not have plug and play, no-brainer installation, and there is no guarantee the spare parts will be available directly to consumers indefinitely. So don't base your decision on the idea the burners just pop in and out of the unit within seconds: they don't, and ordering such parts from the mfr can be tricky unless you reach someone on the phone who knows what the heck you're talking about. They don't always make this easy. Note also, the replacement burner for these units runs $70 give or take, not the $20 you'd pay for a PC burner.
So for your purposes, you might be better off just stocking up on Toshibas whenever you see a low price. Toshibas (and similar DVD-only Magnavox models) sell for as little as $100 if you shop carefully. The Magnavox with HDD starts at approx $229 for the MDR533. The extra cost gets you an HDD you don't really need and a tuner you can't use: satellite systems like DirecTV are self-contained with their own tuner-decoder-pvr box.
One could argue the Magnavox DVD/HDD models are a bit more durable than the the Toshibas without HDD, but it might depend on how you like to work. Recording straight from the DirecTV box to a DVD, you may not see very much difference in burner durability as the drives are nearly the same design. But if you dub a movie from the DirectTV box to the HDD of the Magnavox BEFORE burning the DVD, the Magnavox can do a high-speed burn taking just 18 mins, as opposed to running the burner for two hours straight. Most people who own a Magnavox 533 work that way, perhaps accounting for the much slower rate of worn burners compared to non-HDD models.
In the long run, you might want to consider a recording accessory for your computer. By dubbing to your PC, you have the option of making smaller video files instead of DVDs. Your husband could load a lot of videos onto cheap Micro-SD memory cards and play them on a cheap tablet, instead of toting around a DVD player and discs. I'm helping someone do this right now, actually: they just picked up a Coby tablet for $85 on closeout, for travel use. One can fit the contents of ten dvds on a single reusable $9 memory card the size of your pinky fingernail. Three or four such cards, and the tablet, are much easier to carry and stow away when traveling (plus the tablet has wifi web access). The same cards will often work equally well in a smartphone.