I really just want to know if it is better to do 5 man WoW instances when trying to level up to 70 or should I not worry about getting groups together for instances in order to level up?

I feel that leveling up your character to 70 and running instances can't really be put together well or quickly. With that said it will usually be faster to not worry about doing instances at all until you hit level 70.

When I was leveling up I would rarely ever go into any instance to level. It really just takes too long to put together a good group and while you might make more experience in the instance you will probably get more experience per hour just grinding mobs and questing by yourself.

That's because you will experience a lot of downtime when trying to get a group together and an hour or two can easily fly by while you are trying to put a group together and get over to the instance.

If you are in a guild and it is extremely easy to get a great group together then you might benefit from it greatly.

One thing I highly recommend is that you go into instances only when you have a lot of rest state built up. That might make it more worthwhile to go into an instance.

The few times I would group up with players for instances was when the group was already together except for one person (me) and if I had tons of rest state to work off of.

Even then you have to be careful because if the group is crap and keeps wiping your experience per hour pretty much disappears and just leaves you with a repair bill you would have been without if you would have just grinded and quested solo.

Some people like to do these for gear as well as experience but I found that quest rewards will usually gear you out well enough to level you up to 70 when you can really focus on getting great gear that won't become obsolete in a few levels.