Both are hand block prints from near Jaipur, and both are often printed on Kota Doria. Once you know what to look for, they are easy to tell apart.
Bagru
Bagru comes from a village near Jaipur. It is rustic and earthy: bold geometric and floral motifs in indigo, madder red and iron black. It is often built on the Dabu mud-resist technique.
Sanganeri
Sanganeri comes from the town of Sanganer and is the more refined cousin. Think fine florals, paisleys and vines stamped on a light base, with a crisper, more delicate finish.
Which one to choose
For daily wear with character, Bagru. For a softer, lighter look, Sanganeri.