Given the batt. capacity, excellent batt. consumption it's likely to have*, & superior overall camera tech.
I reckon the dimensions are better than anything else out there right now.
Of course by the time it's out... that'll prolly be different

I have seen it compared dimension-wise to sgs2, & it looks more compact/portable to me.
I haven't seen it compared to xperia arc...

It's not fair to compare it to ip5, there haven't even been any previews of iP5 yet
And so long as it's not out later than Sept (it shouldn't bloody be!) it'll be out at least 1mth before iP5.
And there isn't any proof it will/won't be out much earlier than end-of-Sep for some countries.


*less beastly hw's a big factor, + they realised they can get away w/less beastly & still offer decent UI/MT perf.