Army Builder by Lone Wolf

[SourImplant]

Updates pretty frequently, and you're good until your license expires for more updates. Only problem is, being an unofficial product at the end of the day, you aren't going to have that army's new codex in AB the day (or even the month) that the army gets its big update.

[daddy4count]

Found it! From their licensing page:

Your Army Builder purchase includes one full year of free product updates. At the end of the one-year period, you will have the option of extending the license for a nominal charge. Alternately, you may simply continue to use the expired license. If you allow your license to expire, you will not be able to utilize product updates released after the expiration date.

Sour makes a good point... if you like having the latest and greatest at your fingertips this won't do it.

Also, if you only have one army you can use a single license for years without grabbing updates, since they don't care if you keep using it... they just want you to pay again when you want new shiny things.

I still may have to buy this... but dang if that's not enough $ for lunch and a box of Grey Knights!