Lifco (Little Flower Company) is a publisher in India.
I already owned the Lifco Tamil-Tamil-English Dictionary (the yellow one), having purchased it used on Amazon. I recently ordered the Lifco Tamil-Tamil-English Great Dictionary, directly from their company web page Lifco Books.
If you are not ready to order a book from India just yet, they have an online abridged version of the Tamil-Tamil-English Great Dictionary.
To order books from Lifco within the United States, you will put your items in the shopping cart, but instead of entering your buying information, you will wait a bit and get an emailed quote for your order in US dollars which includes shipping. They have to figure out international shipping to your location. When you accept the price, you then mail your payment to the Lifco rep in the US. When that payment clears, Lifco ships your book from Chennai. I was very happy with the whole transaction. To my location, the total was $19.
The main difference between the regular T-T-E Dictionary and the Great Dictionary is the printing inside. The quality of paper and printing is much higher in the Great Dictionary. I can't tell if the Great Dictionary uses a slightly larger font size, or if the readability is due more to the white space around the entries. The Great Dictionary has more margin space enhancing its appeal. The Great Dictionary also has more pages and entries than the regular one. Both have appendixes of lists in the back of the book.
Both are very nice dictionaries and I would recommend either to a student of the Tamil Language. However, considering that your shipping costs to the US are going to be the majority of the cost, you should get the Tamil-Tamil-English Great Dictionary due to its superior readability.