I agree, also a Must Have in any car or truck I own.
Answering your questions. Second one first. Yes it is comfortable.
Now, is it worth it...? That depends...for me yes. I bought my SILA Armrest from Smartmadness all metal construction, easy peasy install, bolts right to the seat frame, very sturdy and it flips up out of the way.
But not cheap $200 plus $20 shipping.
As a matter of Fact, here is a picture of my armrest I posted on one of your earlier threads.
Link below\/ \/ http://www.smartcarofamerica.com/forums/attachments/f4/25321d1484954989-2-questions-016.jpg