I would think that an experienced GPU miner might be a little turned off to ASIC mining for a few reasons.  ASICs tend to devalue faster than GPUs in my opinion, so while their volatile prices might give you more opportunities for profit scenarios, you have to be quick to act because you can be left holding worthless bricks in the end if you aren't nimble.  There is also more dependency on a single currency, whereas GPU mining gives you added flexibility if one coin's price dips or something.  You're also left with less usability for your equipment, so if regulation or market conditions causes ASICs to become worthless, GPUs will still have buyers in gamers and graphic artists.  Personally, I think GPU miners will be a bit disappointed moving into ASIC mining, but if you pick the right entry and exit points, it can be massively profitable.