Full disclosure: I bought this set used for $30 pre-tax/shipping.

Building Experience: Engines are always fun to build, and it's nice to see a relatively big one making an appearance in an affordable set. Otherwise, the building experience is similar to most sub-$100 Technic sets.

Like all recent LEGO sets, there are far too many steps. Long chains of single-piece steps makes the building process a slog at times. The Bugatti is no worse than any other recent LEGO set in this regard. The unnecessary steps bloat the instruction manual, meaning this 905-piece set requires 162 pages and 308(!) steps. I would like to see Lego make good on its commitment to the environment by reducing the size of its instruction manuals. Save a tree, and my patience.

Parts: The Bugatti comes chock-full of desirable pieces, including 4(!) cams (6575), an assortment of small gears, a mountain of 3L axles with stops (24316), and a smorgasbord of small panels. Besides a couple printed pieces, none of the Bolide's parts are highly specialized for the set. The stickers are not required for this set to look good.

If you're just getting back into Technic after a long break, you might appreciate some of the newer Technic parts, including 18651, 11272, 11214, and 71708.

Playability: For playability features, it checks only the most basic box: the HOG works. The engine is cool, but is mostly concealed by two large Technic plates that do not raise up like an actual hood. The chunky gullwing doors are fun to look at, but a little flimsy when playing with them. The Bolide is clearly made for aesthetic over playability.

I suppose an imaginative kid could flip up the hood and use it as a "frunk," but that doesn't seem to be an intentional feature. On the upside, the roof of the car is very solid, meaning it can be picked up without breaking anything.

Concept: In real life, the Bugatti Bolide is a track-only race car, of which only 40 will ever be produced. It is almost certain that you will never see one in real life. It also doesn't meet the specifications of any particular racing tournament, so you'll never see one on TV in a race. The most you'll ever get is an episode of Top Gear, and this LEGO set.

Why did LEGO turn this car in particular into a set? The Bugatti Bolide is exclusive, expensive, pretty, and very fast - just like countless other supercars none of us will ever see, let alone drive. The concept behind this set is the same bland recipe LEGO has been re-heating for years. 42151 is special, just like everyone else. The Technic lineup needs another licensed supercar like I need a hole in my head.

Appearance: The box art does not do this set justice. This set and its cerulean sister (42162) are prettier than most Technic cars at this size and price point. In fact, I would say it's prettier than most Technic cars, period. The small angled panels do a lot of aesthetic heavy lifting, yielding a wide, sleek stance that isn't overly blocky and flat. The proportions are spot-on. System pieces are integrated cleanly into some of the car's more particular details. The rear of the car is excellent, faithfully reproducing one of the more complex parts of the real Bolide's design thanks to some red lightsabers and small panels. The side profile is as close to "beautiful" as any Technic set can be.

Value for Money: At $50 USD, this set (and 42162) slots in next to:

• NASCAR Camaro ZL1 (42153) - 672 pieces
• Jeep Wrangler (42122) - 655 pieces
• Batcycle (42115) - 641 pieces
• McLaren Senna GTR (42123) - 830 pieces
• Mustang Shelby GT500 (42138) - 544 pieces
• Formula E Porsche 99X (42137) - 422 pieces

If I were buying a $50 Technic set for a kid, I would buy the Jeep (42122). The Jeep offers much more playability with its working suspension and winch. For kids who like to send things flying off ramps, the Porsche (42137) has a pull-back motor.

If I were buying a $50 Technic set for an adult, any of these sets could be a good option. Each set caters to a different combination of taste and values.

At a whopping 905 pieces, the Bolide has the best price-per-piece (PPP) of any new Technic set right now. The Senna is the only other Technic set that comes close to the Bugatti in PPP. Given the aforementioned selection of pieces, 42151 and 42162 are one of the best deals currently offered by LEGO.

Summary: If not for its best-in-theme PPP and solid selection of parts, I would never have given this set a second thought, let alone bought it. 42151 is well-executed conceptual wallpaper. While it is nice to look at, it doesn't speak to me on any deeper level.

I wasn't sure if I was ever going to assemble the set, but I'm glad I did. It looks nice, and the engine is cool. I will probably disassemble it when I need some cams or a steering rack. 3 stars.

Motivation

This set comes with a whole lot of new panels in two useful colours: black and yellow. It also has the 2M lever in the latter colour for the first time.

Thus I decided to buy a copy - at discount - instead of waiting until pieces will become available from Lego shop.

The Set

The box is only filled 50 - 60% which is less than other recent sets. There are four numbered bags. The sticker sheet has same size as the one from the Airbus helicopter; it is bigger than the one from the Ford GT.

The first two bags comprise the base chassis. After that you will work a couple of time back and front on the exterior shape(s). I guess you have to be deeper into aerodynamics or sports car to appreciate all the different twists of the panel-work.

The final model is slightly higher than its box. Because of the black I find it difficult to appreciate the shape.
Without stickers the car appears to be (mostly) yellow from the front:

respectively almost black if viewed from either side:

Unfortunately there is no flap to that opens to have a look at the 16 cylinder engine.

Pro's & Con's

• There is no noticeable colour-coding of parts in that model. In several cases black 2L axles have been used instead of the reds ones. Dark grey 1/2 pins are favour over blue ones. Strangely red 3L pins are used at the front hood.
• The yellow print on the front wheel arcs do not match the part colour:
  
  
  
• Did the set designer got distracted before finishing over here?
  
  The red pin is not required and the black one on the left hasn't got any use at all.
  

• There is a considerable gap at the doors:
  

• The axles at the wheels stick out too far.

• I would have used black axle connectors at the exhaust.

Conclusion

This set might show what kind of car shaping could been at a small call. Therefore many different panels are used. However I think it is mostly lost at this model because the black colour makes it hard to see.

I like the engine setup best of this car.