I am QUITE certain that on this forum you will get more votes for the Simplicity because there are more people here who own them. That is not to say that they don't make a good machine.
The Bad Boy is new and still fighting for recognition in the market place and winning ground every day.
I have a Bad Boy Lightening Z. I understand why you are concerned about the controls due to speed. Have you ever operated another Z before? I have run two other Z's before my Bad Boy and I would have had a little learning curve with the Bad Boy had I not had lots of Z experience before climbing onto it. The answer is YES you will get accustomed to the control sensitivity and never look back.
The only criticism I have for the Bad Boy is due to a strength which is its speed. That criticism is that if you have never run a Z before, it is so fast it will take you longer to learn. If you can drive the Mini Z at all without running over something, then within an hour or so, you won't even know the difference, you will be zipping around as well as you would on most any Z.
You are right, the Bad Boy is a TOUGH built machine, designed for easy maintenance and long life. They are heavy as a result of their toughness and some see that as a disadvantage. If you have a lawn that stays saturated, the weight might indeed be a disadvantage from the stand point of compaction and leaving tracks, but I doubt that this would apply to the Mini.
Not only does Bad Boy make a great machine, but the people behind the machine are as good to deal with as anyone, in any industry, that you will ever do business with.
Don't let anyone try to tell you that they are a new company, poorly funded and all that rot. They are stable and here to stay. That said, even if they went out of business the day after you bought the machine, the wearable parts on the Bad Boy are common items that can be bought elsewhere.
BTW, have you visited their website at:
www.badboymowers.com ?
Good luck with your decision,
Doc