Yes I know they are not the same phone but they are very similar! Hd has better screen and processor I know but still similar. HD Maxx is a great phone no doubt but just stating my opinion. Maxx has better build quality and is a more solid device however it is heavier which is a pro or con depending on the user. S3 has bigger screen and 2gb or ram vs the 1gb of ram on the HD. Both have expandable memory sd slots (up to 32gb for Maxx and 64gb for s3). S3 has the better camera hands down. Both phone have a 1.5 ghz dual core processor. You can't go wrong with either phone!!!! Go to the store and get the feel for them, whatever one suits your style better is the way to go!!!