It seems to be that way with a lot of fonts. I have one from another site and very little difference.
I, too, always look a the J's. Some times they are too plain and sometimes they are too fancy to smuggle up for a monogram. I have even tried to stagger like stair steps to make them work. That is why we are always looking for the perfect alphabet. Right?
Just like jrob, my name also starts with a "J" and I notice in a lot of fonts/alphs that unfortunately the "I" and "J" are so similar. I have even seen J's that look more like the "I" than the "I" itself. ><>
Funny thing is that the I measures 2.87 x 2.60" (h), the J 2.40 x 2.56". You would expect the J to be longer. If you would have to put them together, I would enlarged the J. But I think both are beautiful.
Since my name begins with J, I always notice that. It is very difficult to find a font that everything is the way you would want it, but I always find something in each one that I LOVE!;)