I have terracotta clay but never used it. I’m thinking about using it to make bonsai pots. Any advice from experience you would like to share? And is terracotta a good material or is it too fragile?

Well, clay / terracota pots needs to be cooked on high temperatures to reach waterproof conditions.

I've seen a lot of good ones made out of cement tho', of course is not the same grade as ceramic ones, but surely can be well done.

And it's the fairest way to make your own pots, and it does the job.

Also, I've seen a growing tendency on more organic pots...
This one for example fits nicely on this Calliandra Spinosa:


Here are some other examples on cement pots.

cute jars