I attended a tournament recently that had both Judo and Sambo. Most of the guys there participated in both sports without any difficulty. (There were even a couple of guys who trained in neither but got by on their wrestling ability.) The main difference in appearance was that the Sambo guys stayed on the ground for most of their matches.
My Judo instructor used to compete nationally in both Judo and Sambo and his point of view is that they're basically the same except trading chokes for leg locks in Sambo. Of course, when he competed in Judo, they actually allowed newaza for longer than a few seconds.
I have seen some Sambo throws that look more like body slams than typical Judo throws.