I use the Kobo app for my Samsung Galaxy Tab
since it came preloaded. Kobo is a Canadian based company (headquartered in Toronto) and offers a 35% discount for first e-book. Currently, it has on offer a 20% off selected books until Apr. 10 with the coupon code apr8ww20
. So, it's a reasonably good deal. Do take note that some books are not on tablets yet which means you can only download them into your PC or iPad (if available).
Kobo is relatively easy to use. However, the selection is still very much limited, especially some old books by my favorite authors are not available. I can only find one book by Thomas Friedman! It does have some great classics for free and that's worth looking into.
All in all, there's still much rooms for improvement, esp. with regards to its searches!