I use rinseless all the time. It is quick and easy, you dont waste water and I can clean my work truck anywhere so it is always clean when my customers see it.
Opti-seal is one of the easiest sealants to use, I have done 18 cars and still have over half of the 8oz bottle left, with it you just spray it on the applicator and wipe on I can do the whole car in less than 10 minutes.
They both work about the same. the cg has suds when you wash, and your wash media doesn't stain as bad. other than that I haven't noticed much difference.