omg, the artstyle is sooooo cute!!!
I actually prefer oneshots in general rather than series. Series tend to add random drama just to keep it going (i'm looking at you, citrus).
Most oneshots just focus on the love and wholesomeness without having to pull a "childhood friend that suddenly came bak from abroad" thing. It's is true however that many oneshots aren't very good, but those who are... hell yeah, those are the best yuri i've read.