For the price of a Hydros, I would absolutely buy, either, a stainless steel back plate and 2 wings (1 for cold water, where you'll need more lift, and 1 for warm water that is smaller and more streamlined), or 2 whole BP/W rigs - one with a stainless plate and bigger wing for cold water and one with a lighter (skeletonized stainless, aluminum, or Kydex) plate and a smaller wing for warm water.
That would give you the best rig for each set of conditions and you could still have a chunk of money left over, compared to the cost of one Hydros BCD.
On a budget, a SS BP plus a wing for cold water could also be used for warm water, so you could just buy one BCD (a BP/W), have a LOT of money left over, have the option to just buy a warm water wing later, and still have it perform better than a Hydros.
You could buy this BP/W for warm water. $299, with a 25# wing:
DGX Custom - DGX Singles Harness / Backplate / Wing Package
And this additional wing, for use in cold water. $149, for a 32# wing:
7 Left!**Special Limited Supply**32lb HOG Wing New Style ****Black/Red Model****
That would give you everything you really need for both warm and cold water diving, for $450. And you could buy a stainless steel BP later, if you wanted, to really optimize the cold water setup.
I use this one for cold water diving. It's on Closeout for $70.
Blue Reef Stainless Steel Back Plate
You could have 2 complete rigs for $520 plus the cost of a harness (some webbing and D-rings). I don't know about Switzerland, but here in the U.S., that would still be way cheaper than buying one Hydros.