J&L now carries Seachem. I've only used their Iodine kit before but I think I might try them next when my current kits run out.
http://www.jlaquatics.com/info/397/S...Test+Kits.html
Remember to check for expiration dates as well. After a certain time some of those test kit solutions do get too old and will give you really incorrect readings.
I once compared two Salifert Alkalinity kits with each other. One said my tank was at 6 dkh and the other said 8 dkh. So there are even differences within the same brand...