i personally like the 1000mcg/ml liquid, if you get some slin pins it is very easy to dose correctly each iu = 10mcg. Also, with liquid you can take whatever dose you want but with tabs you have to take in increments of the tab or atleast half....and also 1000mcg at 20ml = 1000 tabs, and can be found for relatively cheap, i've had a 20ml vial for over 1.5yrs now running some now actually