I have the Singer S18 which is actually the Janome 6500 in disguise and I love, love, love it.
If I need an even feed foot for something, I slap the walking foot on.
I did all sorts of free motion on this machine right up to queen size before I got my mid arm. It's a work horse. Can't say enough good things about it.
The only negative I found was that the light wasn't very bright so I bought an LED strip to go under the throat and that fixed that.
Sometimes, a person has to stay within a budget and get the best they can. You asked about two particular machines. I don't know anything about Juki, but I do know that the 6500 is a gem.
Watson