Hi Peter
I agree you cannot beat hot water extraction after pre spray. However on some of the void properties (were carpets are in good condition) but tenant just wants their deposit back, encap works great for me. Don't get me wrong if the carpet is really bad, then extraction only. But most voids I do, carpets are in great condition, just down that their carpets need cleaning after they leave.
Some of domestic properties were custy lives encap is fine if their carpets are in good condition too. I'm not saying encap is better, but when and were it can be used, its great stuff.