I have been using Food Savers for more than 35 years and love them. Now mind you I have gone through several over the years and loved them all. I now buy my bags from ULINE as the rolls of bags cost far less from them. I actually have a brand new one waiting in the wings for when my current one wears out. I picked up this replacement at a thrift store still in the wrapper for $10 and I grabbed it. A good unit will last me 8-10 years. The bags are always the same as far as I know. So anyway I am set for years to come. My Food saver gets used 4-6 times a week depending on what I am doing in the Kitchen.
The quality of my preserved foods when frozen is great.
I also have a small Food Saver vacuum sealer for small refrigerator bags. The bags are a light weight bag similar to a baggie with a vent hole of sorts that you place the little machine over and it draws out the air and the hole closes up. These bags can be rinsed and reused a time or two for dry foods like fresh green beans. These bags are not as easy to find IMHO but the system does a nice job for freshness. You can't really go wrong with Food Saver.
You do not want to confuse vacuum sealing with freeze drying. The equipment for this is far more expensive and the food will last much longer plus it is a different process all together. Good Luck!