What kind of experimental?
Some are safer than others, but mostly its the pilot that makes them unsafe. Such as doing low level aerobatics to show off. That's just not something people do in a C-172.

I wouldn't hesitate to get in an aircraft because it's "experimental". They term "experimental" nowadays is a bit of a misnomer. most of the experimenting was done years ago, now they are built from kits, with the same engines going into certified aircraft.

There is no legal problem with doing the checkride in an experimental, but check with the DE, he/she may not want to get in one.