Ghajini is, well, an ok film. I didn't watch the Tamil version. So, there was no issue of comparison. It's an out and out action film and doesn't leave a lingering taste like Lagaan and Taare Zameen Par. Somehow I don't understand why Aamir had to go through so much rigour to build his multiple packs. I though he managed pretty well in Ghulam minus those packs. The action is not so dissimilar. I gave it a 3.5 simply because it kept me engrossed for 3 hours.
Asin looked fresh, but not ravishing. But appropriate for the role. Jiah Khan was not really great. A bit of flesh here and there and pouting lips is all she managed. I thought Pradeep Rawat as Ghajini was good.
All in all, it is worth watching once, but that's about it. I agree that people thronged the theaters because of Aamir Khan. This certainly is not one of his best efforts.