Everything is tested using MacBook Air (early 2015, i5 8G RAM, High Sierra)
1. jamovi has automatic updates.... very nice touch (who knows maybe JASP has them as well, but I just installed the most recent version)
2. jamovi has syntax mode and nicer GUI (I am a sucker for blue color)
3. jamovi doesn't require Xquartz to run (but it seems to me that it runs a little bit slower) - btw... how come that there are no jamovi menus in MacOS menu bar?
4. tables made in JASP are a bit nicer (less whitespace) when doing copy paste to MS Word, but on the other hand I can save jamovi tables as PDFs
5. jamovi's functionality can be extended with modules!
6. jamovi has motivated me to start learning R - I got my PhD degree two weeks ago, and statistics has become my hobby

7. jamovi has a phenomenal data editor, with row filtering and computed variables - this is the most important feature!!!
I have recommended jamovi to all my colleagues (most of them have pirated copies of SPSS or Graphpad Prism - I have tried a 30 day trial of Prism and IMHO it is too complicated to use and not worth the price with these wonderful open source alternatives).
Anyway... I am about to submit an article on CPR survival with two of my residents (sample of 1440 patients) and all the data analysis was made using jamovi - once the article is accepted I hope that more people will become interested in jamovi.