So It's been a little over a month, and about 200 miles so far. So I'll get my initial impressions out there for this bike.
First off I modified it only a little. I changed :
Handle Bars to OnOne Mary
Stems (the stock adjustable weight over 5 lbs)
Tires to WTB Wolverine Tubeless
Shifters to Deore 9 speed triggers
I have so far taken it everywhere from gravel to single track to blacktop trails and open highways. I have also rode it with my Wife, oldest daughter (8) and youngest Daughter (6). I does excellent on Blacktop The nobbie tires are extra resistance however not as much as I would have thought and the roll smoother than the cheap slicks that came with it. At $60 msrp for those tire I would still say worth every penny. I've taken about 20 miles of gravel so far on it with an Adult and a kid. It rides like a normal mountain bike on the gravel and no real control issues however a front shock nice, but would have made it $500 more expensive. Done about 50 miles of single track with both kids. As a mountain bike if your looking to go fast and clear tons of obstacles you'll be disappointed with this bike. I am happy with it's performance for what I wanted, which was to take the kids out and show them the trails and have fun. The bottom brakets are way to low and leave you with clearance to get over 4" logs the lack of front shock make it very hard to clear any logs at all. However as I said not why I'm riding a tandem off road with 6,8 year olds. We can however get over roots though very tight places (I was surprised at that) and really pick up speed in the flat sections. The climbing on hills is a little sluggish and the back tire spins out here and there (do to 60lbs stoker). Oh ya and the tires are perfect off road the control is excellent.
So overall If your looking for a fun very inexpensive starter tandem this is your baby. It is short enough that a 6 year old and ride it and sturdy enough that and adult can ride with only a minor seat adjustment. It also can take you off roading.