I built the hop paint strainer bag device and used it for awhile. I found that I wasn't getting good hop utilization, especially with late addition hops. The hops would just absorb a good percentage of the wort and after transferring my wort to the carboy, I'd be left with a great-smelling, hoppy, liquidy paint thinner bag full of hops. However, that indicated that all of that hoppy goodness was being left in the brew kettle and not in my carboy. I agree with the people that have said that you really have to increase the hops to get what you're looking for when you use the paint thinner bags.
Then, my PVC collar melted just from the steam rising from my boil (which is not a very vigorous boil at all). So, I no longer use the strainer bags.
I'm still looking for a good solution to the hop straining problem. Ideally I'd whirlpool to get maximum hop aroma from late additions and then siphon (I don't have a drain valve on my kettle) with a hop filter to keep the hops in the kettle.