[Hugh]

In my opinion, for philatelic purposes, there is really very little to choose from when it comes to light-tables. They're much the same. I bought mine from Amazon.ca. 

My advice, therefore, is:

1 - Don't spend a lot of money. It's not necessary if you only plan to use it for examining stamps or revealing the watermark on old letter paper. Mine cost about C$50.

2 - Decide on the size you want. You can get small ones (good enough for stamps and they take less room). Mine's a bit bigger, about 20x30 cm ... because I work with old folded letters and documents. I also use it to help with reading cross-writing. It also helps with photographing some watermarks on stamps. 

3 - They're LED and don't need much power ... so, consider buying one that has a USB cord to your laptop or computer. I have one that has a micro-USB to USB cable. I leave the cable permanently attached to my iMac and then, when I need to use the table, I put it on the desk and just plug it in. That's one reason why they don't cost much. They don't need an electrical outlet. 

Here's my light-table (to the right of the scanner) and a close up.. It works fine for me. 

   

   

Cheers, Hugh