First things first, forget the Micromax devices since you can afford to get a phone of a reputed brand. Now that Micromax is out of the equation, dont bother considering it unless you want buggy software, chinese chipset, service center headache and no updates.
Now you have 3 devices:
LG L9
Samsung Galaxy Grand
Sony Xperia SL
All of them are good devices in slightly different price ranges differing in Rs.2k, each with their pros and cons. Go to any electronics store and try the 3 devices first. If you are mind-blown by any one of those then look no further and get that one. Each one has different likes and needs, so all 3 phones are best depending on the person, you cant go wrong with any of the 3.
IMO xperia SL is the best as suggested by SAM , most balanced phone of the 3 devices. It doesnt have Jellybean yet so you will have to wait till it gets updated, which will improve the performance and UI. Still even on ICS, its a damn good device and best under 25k. It is available for 22k in some places which makes for a good vfm deal. Best CPU and GPU, Best camera, Best screen quality, Largest Internal Storage
Samsung Grand is available for around 20k. Largest screen, but lowest resolution. Many unique touchwiz features like multi window. Best Gaming performance because of lower resolution. The SL has better raw power but Grand has lowest resolution which enables it to overcome its weakness. Comparing CPU performance SL is better, so SL will be better at loading times, editing work. GPU performance will be better on Grand, because of earlier mentioned reason.
LG L9 is the most VFM device of the 3, since it is available for 18k and once was even available for 15k on HS18(total steal!!). It has 80-90% the performance of the SL in CPU and GPU depending on the application. It has good screen and pixel density. It will update to Jellybean too, which will improve the performance. Least internal memory(4GB) which is enough for most people though. Camera is ok.
i'll check out the galaxy s advance and optimus L9
