Okay, I'll be the one dissenter. DH and I are germaphobes and always carry our portable booster seat in the bottom of the stroller basket. It straps to any regular dining chair and we like that it has its own tray so DD does not touch the table at all.
We have a routine down now...I hold the baby while DH straps on the highchair and then wipes down the parts of the dining chair she can touch. Takes about one - two minutes, then I can put DD in the chair, click on the tray, and then we can relax for the rest of the meal knowing she is in a nice controlled spot.
We actually use this same chair at home, and just keep a second one in our trunk for restaurants, whether at home or in Disney.
This is the one we use. I like that it is all plastic and very easy to clean. I hope this link works:
http://www.amazon.com/Fisher-Price-...2RWQ/ref=sr_1_1?ie=UTF8&qid=1323140988&sr=8-1