I just fitted a trail gator to my bike and that of my daughter now that she has outgrown our bike trailer - it's just too much of a squeeze with her and her brother on board. I had worried that the single wide tube on the childs bike (A Raleigh Superstar) might prevent it's fitting but the child's "Receiver" will fit up to 105mm which is good because that's just about the width of the tube on her bike. Issues with bolts coming loose seem to have been fixed by using nyloc nuts so it looks like the manufacturer is taking note of comments like this on various websites.

The most fiddly part is fitting the child's receiver, this consists of some long U bolts which can be awkward to do up unless you have some deep sockets or tube spanners otherwise it's a lot of half turns with a spanner. The spacers can be fiddly, but are slotted so you don't have to dismantle the whole thing to adjust the angle of the kids bike.

On the adult's bike fitting is relatively straight forward, the kit also comes with a clip to "Park" the towbar when the child feels like pedaling and this is probably the only part that worries me as it looks a bit flimsy.

Riding is odd to start with unless you are used to a bike trailer, take the instruction manual's advice and ride solo with the kid's bike attached to get the feel of it, if like me, you have used a bike trailer the feel is about the same. With the child on board it takes some getting used to, particularly if they are still using training wheels. Here I advise you run around the block or find some wide and quiet roads for you both to get the feel of it before attempting a more serious journey.

Looking at the comments an addition is required. Take a look at the photo, the point of contact between the adult and child's rear wheel is very long, now bear in mind that the childs front wheel will be some 50mm above the ground and you have a shallow breakover angle. This means trips on tow paths and roads will be OK but you will have to leave those trips through woods etc for a while longer. It will take small humps and on my kids bikes the compression is partially mitigated by front suspension on their bike.

Accesories:

This does not work with fixed training wheels, trail gator do some flip up wheels which seem to do the trick so this is easily fixed. You may also want a mirror to check on your child as turning to check while they're wobbling about is a challenge.

The bar is not easily transferred between bikes due to the fitments although the bar itself uses a QD fitting. Fortunatelly the adult's and clild's receivers can be bought separately from a lot of web based cycle shops so you can easly set up another adult's or childs bike with a tow point if you want to swap the tow bar with your partner or tow different bikes.