Karts vs Bikes: Pros and Cons?

Differences between bikes and karts are generally this:

• Karts can charge a full mini-turbo (yellow sparks) if the turn is long enough; bikes can only charge a half-mini-turbo (blue sparks). On courses with many sharp turns this can result in karts getting a decent amount more speed boosts.
• Bikes can do wheelies and karts can't; during a wheelie you get a constant speed boost, but you can't turn much at all and hitting a wall or opponent will bring you to an almost complete stop. This means bikes will usually pass karts on straightways (since the stability weakness and turn prevention are generally not enough of a downside to constantly going faster when you can just un-wheelie at any time), which are generally more common than curves you can do a full mini-turbo on. As far as I know all the world-class time trial runs are done on bikes just for this reason.
• Both vehicles can reduce the effect of a POW Block by making a trick motion as it hits.
• In general, every kart has a bike that is very similar in stats, called a "counterpart" by the Super Mario Wiki. So if you want to jump between the two types there will always be something on the other side that acts mostly the same.
• All karts drift "outwards". Some bikes drift "inwards". It's hard to explain what this means/understand how this works but you will certainly know when you pick a bike that does it.

One things karts have that bikes do not is the 2nd level of boost from drifting. Doing wheelies also has a downside. When you are doing a wheelie and get bumped, you lose a lot of speed/momentum. I also think it is the act of doing a small hop that evades the POW and doing a wheelie is just an easy way to achieve that. I have not tested trying to dodge with a kart.

If you look at the actual stats for bikes vs karts, you should find some differences between average top speed and acceleration. (I think, I have not looked at the stats in a while).

Disclosure: I usually go with a bike. that bike being the Flame Runner.