Now thats a confusing question and mostly asked since ace is the most popular android in this price range.Firstly let me tell you that Ace S5830 is around 8 months older than Sony LWW.Meaning the technology offered should be better on SONY. Each phones has its own benefits and Minuses . Basically Sony Phones are generally costlier than Samsung , HTC etc. of the same features & quality.And i cant choose a phone for you as it depends on the way you use. But i am not leaving you in the dark shadows.I can just help you choose your right device. Here's what i recommend each of the phones for .
Calls - Galaxy Ace [ Larger Battery , Better talk time should be expected ]
Music-Sony Live With Walkman[ XLOUD ,Walkman Button ]
Gaming-Galaxy Ace [larger Screen =Easy to play ]
Videos,Movies-Sony Live With Walkman [ Good Display ]
Portability -Sony Live With Walkman [Smaller Size ,Fits pocket easily ]
Rough Use-Galaxy Ace [Display is guarded well all the way,Keep in Mind Ace is not Scratch resistant]
Looks-Sony Live With Walkman [ :-)]
Apps : Sony Live [ 320Mb Free memory available ,Rooted roms can give upto 420MB + Free space]
Sony Advantage : 320Mb Free ram available,Faster processor ,Flash Support,Front Cam,Android 2.3+
So, now its up to you to choose you gadget. if you are too much Confused ,just choose your favorite brand.
Keep in mind that Live Costs roughly 1000 [~20$]-2000[~40$ ] INR greater than the Ace .Recently Samsung has launched Galaxy Ace Plus ,but I am not making a comparison there as Ace Plus has got a worse popularity due to its Poor quality and higher price.Personally I recommend Sony Live for its performance.