I'm still learning about the different options, so I can't give a definitive answer to this yet. By I can tell you about my personal experience so far.
I currently own two light boxes, both of the slim LED variety. First is a Huion A4 table which I bought on eBay. It works well, except that the power supply that came with it caused some flickering (I swapped it out for another standard USB power supply), and it has a slightly cold color cast.
I also have an Kaiser slimline plano light table, which is smaller and more portable, has a built-in battery, and a warmer color. It's advertised as being full-spectrum, which could possibly give more accurate colors, but I haven't tested that yet. You can find these online at B&H, or many retail stores. At $118, it costs probably 2-3 times as much as one of the cheaper light tables. (Disclaimer: this table was sent it to me for free by the US distributor when then they heard about FilmLab).
I will try to add more specific information about light tables before the FilmLab beta is released, so backers can have a chance to order a good light table ahead of time.