Stamina Templars can provide a high damage output in both Single Target and Area of Effect (AoE) damage. They also have an easier time sustaining their resources, meaning they don't run out of Stamina or Magicka easily.

Is stamina or magicka Templar better?

for soloing the questzones and normal dunegons, it doesnt make any difference. stamplar has better damage naturally, but for solo stuff magplar is great, since you can just jab (crescent sweep) everything down. you dont even have to think about healing, because jabs heal with every hit.

Is stamina Templar fun?

It's a lot of fun to play. But... if you're comfortable and experienced with magicka builds, and if you haven't rolled a magicka Templar, you will be well-rewarded for trying one now.