Most of my opinions and our collective opinions about reviewers' opinions are in -
http://androidforums.com/htc-one/69...deo-talk-ultrapixel-more-tips-discussion.html - and we keep that updated with review links - and I believe you've seen that. (?)
I do think a lot of what's offered will come down to the apps.
And I mention that because HTC just did a fair upgrade to theirs, possibly putting a lot of reviewed opinions out of date. And tbh, most of the reviews we had were definitely not done with the production HTC s/w and I'm suspect on that point for the SGS4 photos as well. And the reviewers are hard over on evaluating at auto/default only in most every case. Ok if that's how you use a camera - I _never_ do.
So - the comparisons and photos you've seen are probably either one or two generations out of date on the HTC s/w.
As mentioned by my pal novox77 in the above thread - the iPhone simply has a superior multi-coated lens. While all three phones now have very good cameras, the two Androids have to be better in other areas because of that weakness.
You can still mop the floor - in detail - with either Android using a digital camera at 3.2 MP. I've got one, I'm rather certain of it.
Why? That camera has a larger sensor and a better lens.
Yes, there are enlargement/cropping limitations as you sacrifice pixel count. But the apparent noise can be a problem with enlargement/cropping as you increase pixel count.
The One's advantage is not just in larger pixels to reduce noise - it's also in it's F/2.0 aperture and it's sensor being 1/3" rather than just 1/3.2" on the Samsung. That's a 15% larger area to gather light and more light flowing in. More light -> less digital noise.
From similar experiences last year comparing the SGS3 and One X, and from having owned several HTCs over the years I'm also certain that HTC's biggest mistake has always been in their jpg compression.
I'm running a modified camera app on my last-year's HTC that allows me to scale back their compression - and it makes a world of difference on image quality.
I've requested that HTC make that a standard adjustment feature, but I've not heard back on that.
This shows very well why compression is a serious issue if you're not already familiar with it -
http://androidforums.com/htc-one/69...pixel-more-tips-discussion-2.html#post5687501 - especially visit the wikipedia link for picture/compression comparisons
I'm using a root-modified app on mine, you won't have that to evaluate, so here's an app that doesn't have that issue, you can set the jpeg compression quality -
Check out "Camera JB+"
https://play.google.com/store/apps/details?id=com.moblynx.camerajbplus
It's not free, but may well be worth it to you. Even going to the SGS4. Once the new and shiny wears off, better camera apps are the first thing people go for - the Samsung is no exception for a lot of folks.
And if detail is important to you, you do NOT want jpeg compression holding you up.
And you'd mentioned that you'd likely post-process for saturation, rgb adjustments are built-in to that app.
I've not used it, but I've heard a lot positive about it.
I use "Photo Enhance HDR Editor Pro" for quick adjustments -
https://play.google.com/store/apps/details?id=com.wheadon.photoenhancepro
And this one is probably next for you, I find it's very good, you can zoom in close to paint red eyes, "Red Eye Removal (Free)"
https://play.google.com/store/apps/details?id=uk.co.justgoodapps.free
You may have noticed SLRdude's picture's, his are rather good and he recommends this one -
https://play.google.com/store/apps/details?id=com.niksoftware.snapseed
Hope this helps.
PS - every digital camera I've seen lets you adjust jpeg compression, although they often call it quality vs file size, that's what that is.
It's simply an essential feature if you care about detail.