Their reputation when I got mine about 7 years ago was that whilst expensive they were the best available, for the size of the machine I'd advise the biggest one, you will be surprised how easy it is to fill and in terms of footprint it doesn't take up any more space ( either way it's a big chunk of space) I got mine for jerky ( he said salivating) these days it plays a major role in reloading - drying my brass, but they are marvelous machines, even more so if you are a gardener, we had a phase of a liking for Mousaka, which coincided with Lidl having a half price offer on Aubergines, I think I got about a dozen of them, enough for five batches of the meal, dehydrated them, vac bagged them and put them in the freezer.
If used wisely by preserving your home grown foods or special offers, I would think you could actually save a few bob overall, but given the initial outlay, and price of electricity you would have to work at it
and you shouldn't consider it doomsday prepping to own one, we wouldn't be without ours now.
I have a strategy, it's not written in stone, nor can it be, this scenario has too many variables, everything about it depends on those variables, being specific is not possible.
