Yup, heavier than XT. Perfectly nice cassette, just doesn't make much sense to buy one.
20-25g in it, it's not the end of the world.
Also, it does make a lot of sense to buy one when you can get it brand new for £25, and an XT was £40+ as was the case at the time I needed a new cassette… Agreed that it's not quite as good as an XT though.
Oh, and only top 3 rings are on the carrier. Mine has only been on a steel freehub on a Shimano XT hub so far so no issues there, haven't tried it on a Hope freehub yet (my Hope rear wheel has an XT cassette on incidentally).