I call shenanigans on the $4000 SV rig stuff. Commercial kitchens will spend $4000 on an immersion circulator alone, and that's before the cryovac or whatever they're doing to seal food.

If you want to (a) make watermelons with the texture of a strip steak or (b) cook SV in huge volume, you need to investigate high end equipment.

Otherwise, the concept behind SV is extremely simple. Precisely controlled temperature over long cooking time. The $120 PID controllers do that job just fine.

What have you read that says you need a cryovac to do SV well? The Baldwin guide actively endorses the ghetto setup, and there are numerous blogs of people succeeding with it. The Keller sous vide book isn't a home cookbook any more than the Alinea cookbook is. You're not making French Laundry food at home no matter how you equip your kitchen.