It’s really great to read about these experiences from different people and still find similarities. Positive confirmation, indeed. 
Anyway, Buer is definitely an excellent spirit. I haven’t worked with him yet, but we’ve interacted a few times already. He immediately came to me when I felt a pull to draw him in my journal last year. And like the other poster here mentioned, I did see him as the type to sip tea, reading books by himself and all! I saw him in a garden though. So I ended up drawing him as reading a book under the shade of a huge tree, with a pile of books and two (pet) animals cozying up beside him. I also felt randomly inspired to write funny but factual captions about him at the back of my drawing after, replacing the lyrics of a popular song’s chorus. It’s embarrassing, but it went like this:
to the tune of Mambo No. 5
A little bit of flora in my life
A little bit of fauna by my side
A little bit of moral philosophy
And also natural philosophy
A little bit of Logic Art in the sun
A little bit of herbals all night long
A little bit of medicine here I am
A little bit of you makes me your Buer
I sang it aloud, apologized repeatedly to Buer for even getting such an idea from god-knows-where and was determined to throw it away for good when I felt his presence. And I shit you not, he actually loved the crappy drawing and the mini-song. I was slack-jawed because he was laughing good-naturedly and even had me singing it repeatedly, when I was very convinced the whole thing was rude. To say that we got along right off the bat was an understatement.
Ever since that day, he’d come every now and then just to say hello and stuff. I consider him a dear friend I won’t hesitate to work with should the need arise. His energy is very intellectual and jovial Sagittarius to me. I agree that he is strongly responsive and easy to call on, talk to, etc. He likes popping up during my divination sessions about other spirits too. He makes me feel at ease and cheerier than usual. At times, his personality reminds me of the ideal older brother I wish I had when I was younger, so maybe that’s why I’m just so fond of him. 
About the vanilla bit, I did see him eyeing my vanilla-flavored/filled Oreo softcakes. Prior to knowing that, I remember randomly thinking of him whenever I eat it or suddenly spacing out and staring at the words, “vanilla” on said softcake’s wrapping. When I saw this forum back in my lurker days, it made me laugh aloud. I could swear I saw Buer was laughing with me too… along with emphasized imageries of the softcakes, of course.