What are the difference between V-tail and Normal? Are the harder to fly? Does it matter or just personal preference, I have notice a lot of sailplanes have them.

Thanks

In theory, they have lower drag, hence their use in some sailplanes and some pylon racers. To use one, you will need a radio capable of V-tail or elevon mixing, although it is possible to build a plane that uses mechanical mixing.
They are no more difficult to fly than standard tails.

When flying you can't tell the difference.

Most of the V tails react a little slower. I can roll a gentle lady glider with a regular tail, but I can't roll any of my V tail gliders. In full scale, the V tail Bonanza shimmies when it flies. The guy in the back seat gets it worse than the ones up front. I don't care for them very much personally, but some really like them.

Yup, flying a full scale V-tail Bonanza is a bit interesting the first time you do it, especially if it's windy! That little side to side oscillation, although slight, takes a couple of flights to get used to. Once you get past that, they're great performers, especially if you're flying one that 's been injected and turbocharged!

One advantage of V tails is that the tail is less likely to be damaged if you belly land the plane. A standard tail plane will drag the H stab in the grass, but a V tail reduces the stress on the tail when belly landing on grass.

I think that that's called "dutch roll", the plane's yaw-roll coupling causes yaw to roll the plane but then the roll creates adverse yaw which then rolls the plane the other way and repeats. Conventional tailed airplanes will do this also if the verticle fin area is too small, or so I have read in free flight trimming articles. Too much verticle stabilizer area and the plane becomes spirally unstable. The key to free flight planes is just enough verticle stabilizer area to damp out dutch roll but not enough to cause the plane to go into a spiral.