I'll try to give a balanced view between i4 and the HTC Desire HD, both of which I own and use on a daily basis.
If I were an outsider with little knowledge, I would see the relentless Android software advancement, coupled with god knows how many new hardware models launching almost daily from various manufacturers as very daunting. I really do think it could or has potentially harmed the growth of the platform.
As Joe Bloggs.. the i4 looks and feels, dare i say it, easy.. 2 hardware levels, one app store etc.
Here are my views on the key elements of the phones..
UI:
I call the i4 UI a get what you see interface.. by this I mean it's very simple to operate but should you really want to mess around, there isn't much you can do. On the DHD it seems I could play all day with various settings.. great if thats your cup of tea.. but not so great if you just want to pick up the phone, do the business and put it back down again..
Both I feel offer plus points in their own field..
SCREENS:
I love the size of the DHD screen but I wish it had the definition and depth of the i4.. but I think that will come within a generation or two
APPS:
umm.. difficult one this.. Again, I do love the simplistic way the Apple store presents the whole, pick and pay profile. It's clean, safe and simple.
The Android store is good but I really do find myself second guessing if the apps are safe to load.. With the OS being open source.. (trust me I know a lot about open source) I do question the stability and compatibility of the apps.
BATTERY:
Both seem pretty good to me. I easily get a day from the i4, likewise the same with the DHD
PHONE CALL QUALITY:
This is easy.. The DHD beats the i4 into a cocked hat.. the i4 has always had issues with sensors.. every time bar none, I get calls either stuck on hold, cut off or muted because the sensor doesn't realise i'm holding the phone to my ear.. it's terrible.......
Speech and hearing quality seems better on the DHD to me also.
MUSIC / MEDIA
First, music.. I'm probably my own worst enemy here.. I do use itunes.. (i know.. i'm a numpty) but it's something I just started to use and have grown with it.. The i4 interface with itunes is fluid. I've yet to find a good way to get my music into the DHD..
Video.. I find the movies I have sent to the DHD don't play smoothly, there is a lot of stutter on the movies. I'm trying different players.. yet to find one I like.. (using high speed 16gb SD card).
The i4 also suffers from the Apple lockdown on codecs.. but this isn't such an issue now as VLC player is available and is very good.
QUALITY OF BUILD.
I think both are well made and good looking phones. In terms of style, my personal preference goes to the i4.
EMAIL.
This is quite important to me as I get a lot of emails everyday and both of these phones need to be easy to use in terms of text entry.
It may be a little unfair to judge the text entry at this point as I've been using the i4 for much longer... however, I will make the observation that the accuracy of finger placement on the i4 seems better than the DHD
I have to say that it's a difficult decision to decide scores for these two phones, but, out of 10 (10 being best) I would rate them over all as:
iphone 4 = 8 out of 10.. Fantastic quality screen, safe shopping environment, good looking. BUT.. locked down software, expensive and very poor with phone calls.
HTC Desire HD = 7 out of 10.. Good size screen although not enough definition for me, good choice of apps, nice sturdy design, BUT.. open source security issues could scare some people. The endless Android updates and new hardware launches could put some people off.