ot- karaoke dvd vs vcd cd+G advice

I've been wanting to buy a karaoke machine for my daughter for her birthday.
There seems to be so many formats for karaoke machines. Can anyone advise
me as to whether or not it is worth getting one that supports the dvd or vcd
format or is cd+g good enough?

Also some DVD players (which can also play cd's and mp3's) have a karaoke
option. do these machines use dvd karaoke format, or just the regular cd or
cd + g format when it comes to playing karaoke?

I have asked in the stores and I get "don't know" or "buy it and if it
doesn't do what you want return it".

Thanks,

Sid...