I don't have a Juki. A friend has a Juki and I play on it occasionally. I am still apprehensive with the speed with which it sews but otherwise it is a great machine. I am sure it would be easy to get used to if you had one but I am very happy with my vintage machines. I am not sure which one it is but I think the TL98Q (?).
To be honest with you I don't do a lot of stippling and no micro stippling. What I have done requires more practice but that is not the machines fault, it is operator inexperience. FMQ requires practice and if your machine has the ability to do FMQ and you take the time to practice you will eventually be able to conquer the skill. There are quite a few quilters on this forum that use these vintage machines exclusively for their FMQ and they swear by them. For the money I don't think you can go wrong. Ann