Pfft. I've owned the Galaxy S, Galaxy S2, Galaxy Note, Galaxy Nexus (I know, not really a Samsung Galaxy phone like the others), Galaxy S3 and Galaxy Note 2. I'm all Galaxy'd out.
I'd always flash AOSP/AOKP roms on them because I preferred it over Touchwiz. In the past Samsung used to have the best hardware with fast processors, sd slots and all that, but now I'm going to the One because the S4 doesn't look impressive to me at all. It's a spec bump (which is expected) and more software gimmicks. The One looks like it has a killer build/design, Sense looks more tame and less annoying than TW, and I still have the option to flash AOSP roms on it.
I think Samsung making all plastic phones with ugly aesthetics and charging full price for them is pretty lame. The S4 to me just looks like a gimmick 'phone store experience' phone. Where a customer goes to a phone store, looking for a new phone to buy, the assistant shows them the S4 and goes through a bunch of gimmicks like waving across the screen, looking away and all that nonsense and the customer is initially impressed and picks the phone up. It doesn't look like a phone with a focus or an idea on what it's trying to achieve for the user. It's like the devs at Samsung just scattershot a bunch of ideas on a whiteboard and tried to implement as many as they could before release.