As far as installation and usage is concerned I can say the plugging is fantastic. It looks simple and I wonder if it is efficient or not? Never mind, re-captcha is too confusing, I had to reload several times until I find a combinaison I can read. Not to speak complaint of elders!
This one is straight forward and worth to be tried.
I look at several other Captchas. I liked also another one, but prefers jproi one.