As Shadow Titan said, it's best if you're a magic-based character.
PROS:
1. Being a Vampire Lord makes you very powerful. It can save your life if you retreat and go into your vampire lord form.
2. Unlike a werewolf, you can use this power anytime you want, as many times as you want, day or night.
3. Sprinting as a vampire lord makes you move faster than a horse.
4. The bonuses you get from the Necromage perk helps a lot with enchanting.
5. Even while in the sunlight, having magic regeneration robes/armor and taking advantage of the Restoration perk "Respite" will keep all of your stats at 100% rather effectively
6. Even in the daytime, you will slowly regenerate health and stamina while in Vampire Lord form.
CONS:
1. The sun is your worst enemy and will hinder you every day.
2. If you take advantage of the blood-stained arrows, you must shoot the sun every day. (That was a big disappointment for me)
3. Shooting the sun isn't always an option. There are several places in Skyrim that are too cloudy to even see the sun, but you still have the effects of the sun's power draining you.
4. If you are not a magic-based character, you are forced to run into dungeons to recover.
All in all, I would highly suggest becoming a vampire, especially if you're a magic-based character, but it's best to join the Vampires right from the beginning. You can still be a vampire as a combat or stealth-based character but you'll be much more powerful with magic on your side.