"Having built two other big Technic sets, I was eager to quickly grab the Air Race Jet for a few reasons; I'm a general aviation fan, it had motorised parts that added to the value, and I just love the satisfaction of building big things.
Coming in at over 1100 pieces, this is the biggest set I've dealt with thus far, and due to having to build it out of work hours it took perhaps a few hours longer than would be expected. This is no downside, however. When building the jet, it seems to take shape out of nowhere, as you start off at the fuselage and before you know it you've attached the nose section and the landing gear.
The two things I love the most about this are that the battery pack and motor are included, which saves me having to fork out stupid money for a power function set, and linking in to that are the powered undercarriage and VTOL surfaces (the moving parts of such being the upper and lower fuselage fan covers, the fans themselves and the exhaust nozzle and the trailing-edge flaps).
After that is the attention to detail, specifically the two contra-rotating VTOL fans located behind the cockpit, as well as the little throttle and control column on either side of the ejector seat, which I found to be a cute touch.
If I have two gripes about this set, it's that 1) the bags aren't numbered. Even though I spread out the pieces into different containers, it still took my partner and I the best part of 5 minutes trying to find one tiny solitary piece that was not used anywhere else in the model.
2) The two panels under the nose, even when secured with other plates, are wobbly and loose. I would have hoped for a little more stability, but it's a minor annoyance since this will be sat on display, rather than be a heavy-play item.
Overall I would recommend 42066 to any dual Lego-and-Aviation fan. Watch out, though, some of it is quite fiddly."