Ford took me about 5 hours because I was unfamilliar with the shorcuts that the Modnation "sticker" interface offers. The kart took about 3 hours because I basically have all the tricks of the customization down pat.
The game itself has different appeals for different people. There's only 4 power up types: Rockets, sonicboom, pink lightning, and a booster power-up. Each of these power ups have 3 stages: basic, intermediate, and beastly. Apart from that you can attack you enemies with a sideswipe.
Then there is the point system. Depending on how well you drift, how well you air-draft, how much air-hang-time you get, how many other racers you take down with attacks, how many stunt spins you can manage, you are awarded points that fill up a yellow bar. This power bar can be used for different things: Boost, Shield, Sideswipes (costs minimal points), and trigger activation.
Overall, the racing itself (including the brief career story mode) is solid and fun. There are those that don't find lasting appeal in that alone though, and have stated that they'll probably trade in the game after 2 to 6 months.
The real fun is for those with the creative spark. If mastered, the customization offers a virtually endless set of possibilites as far as the mods (characters) and karts go. The track editor is slightly more limited, but more than satisfactory. You can build a full functioning track in about 5 minutes or less, or you can make something a little more creative given a good amount of time. It's up to you. Not only that, you can upload your mods, tracks, and karts for people to download. 12 player online races, and new/useful DLC every week or two enhance the game further.
It doesn't have a battle mode, and load times are lengthy but that's all that keeps it from perfection. X-play gave it a 4 out of 5 and that's a fair judgment, IMO. If you like kart racers, and/or LittleBigPlanet, you'll enjoy it.
Uncharted 2 Machinima Voice Actor. Currently playing Sully and Lazarevic. Add me on PSN if you want to get involved: Geo_Chronic.