Micromax Tab P666 is a very good tablet with some amazing features and configuration. It is a 8 inch calling tablet with a screen resolution of 1280x800 pixels.
Viewing angles are great as it has an IPS screen. It supports single gsm sim. It has android kitkat 4.4.2 with 1.2 ghz intel atom dual core processor.
You will not find any lag or hanging problem if you play some basic android games or open multiple android applications because of its 1gb Ram. I found its internal storage of 8gb insufficient because I cannot keep more than 2 hd movies in it and I love watching hd movies on it because of its big 8 inch hd screen. So I had to buy a seperate micro sd card to increase its memory.
It has a 5 MP Rear camera and 2 MP front camera and both cameras are good but not excellent. The good thing is that they both are autofocus cameras. 3g and wifi internet also worked smoothly without any problem. The best thing about this tablet is its batery backup as it has a 4400 Mah battery which is really amazing. So it is a very good tablet with nice features.