biostats 1, for me, seemed like a faster paced sequel to stats 1, just using health examples. Taking stats 1 is really helpful because they spend quite a bit of time on frequency histograms and the tables to make them. In my biostats 1, the book assumed knowledge of frequency histograms and the section on them seemed to be review. It may be difficult if you had not seen it before. Also, the table you use to solve them is the same as you need to set up for ANOVAs. Having done it before makes it that much easier later. Also, taking stats 1 makes the probability section of biostats 1 a breeze. Stats 1 moves very slowly and you have plenty of time to "get it". Biostats is fast paced. I would highly reccomend it.
My school does not offer an undergrad biostats course. If your does, take it. Anything to make your life in grad school easier, because not all classes will be easy. (Honestly, biostats 1 was really easy for me because I had already seen most of it before. It allowed me to focus more time on studying Epi, which I needed.)