I like how the first one you posted is foldable and can be used in a variety of different ways. I didn't run across that one when I was doing my research.
I have one called the "Snoozer," which I think is similar to the second one you posted in terms of how it works. I really like it. Even in the first trimester, like you, I was getting aches and pains from trying to sleep on my side all night. I don't really understand the mechanism of how these pillows work (I mean, other than being soft and comfy and all that ), but I *think* it's having a pillow between my knees that somehow "aligns" me better and prevents the hip and back soreness that I was experiencing before. The body pillow aspect also gives me someplace to put my arms (I just sort of "hug" the pillow) whereas without it, I tend to put them in an awkward position and my hands fall asleep. But I would really say it's the cushion between my knees that provides the most benefit. I can sleep all night in the same position and not be stiff and achy when I wake up, which was definitely NOT the case before I got the pillow. I still occasionally wake up near morning, get annoyed at feeling "constricted" or "crowded" and chuck the pillow on the floor, but there is far less waking up, tossing and turning, etc. than before I got it. Before I felt like I was constantly waking up and turning from one side to the other.
I don't know about the Snoogle (and the first one you posted looks quite compact), but the main annoying thing about the Snoozer is that it's pretty big. (That and the pillowcase is kind of hard to get on, but I figured it out pretty well now and it's not too bad.) I find myself wishing for the first time that we had a king-size bed. There is room for me, DH, and the pillow, but if I stretch out at all, I start encroaching on his space, especially if the cats are in bed with us.