Depends on what you mean with "just as good". Why is the S3 good for you (apart from its size)?
I see a tendency for phones to be used as a computer (for mail and chat and Facebook) or as a movie cameras (to make a movie) or as a game devices (for playing computer games) or as e-reader (to read the newspaper or an e-book) or as a device to view movies.
For those uses you need a bigger screen than just for making a call or sending a sms. A phone with a smaller screen would definitely be worse in stead of 'just as good' or better.
Your choice to find the right device for what you want to do with it. Or two devices, like a feature phone to phone and a tablet to use as a computer, a camera, a game device, an e-reader and a movie viewer.
I have to galaxy s3 and I love my phone, the only problem I have with it is the size. It is to big.
I have an upgrade coming up and I am starting to look at other phones but, unsure what would be the best choiice.
I was wondering what other smartphones would be just as good but not as big.
Any help would be really appreciated.