I've got 2 70 with their epics and a 68 that will probably have her epic when she hits 70. They do make things faster and easier. I do just fine in instances and in some cases even top the charts.
However I've done both. On my Spriest I got her FSW and spellstrike sets before her epic. I think the trick is to find a good medium. A lot of people hit gear hard and a big part of that is gems and enchants. People will easily spend 100's of gold for blue gems instead of the slightly lower green ones at a fraction of the price. I'll take 2 less sta or 2 less spell dmg for a ton less gold and use what I save to fund my epic flyer.
Once I get my epic flyer a ton of dailies open up. The nice thing about this is I can mix my dailies up better. One day I can do 10 dailies and the next I can do 10 different ones. Makes burnout less likely. Some dailies I hate and I can skip them completely but still cap 10. Another thing is I can grab 20 daily quests finish them all but only turn 10 in. The next day after dailies are reset I have 10 all ready to turn in without doing anything. I can turn them in and forget about them for a day and do something else.
The thing about gear is that when you first hit 70 it's still getting replaced fast. I don't enchant anything unless I think I'll have it for a while to make it worth it. I also believe that if you're trying to catch up to friends or a guild in progression that gear > epic. Even still if you buy the lower priced gems and enchants for now and upgrade them later you've got that much money saved for your epic.
The biggest money maker is actually saving it. I have a friend who has wanted an epic flyer forever. His biggest problem is he's a shopaholic. I had him download moneyfu for his fubar mod. It tells you how much you've made and spent each session, day, and week. It shows if you've gone ahead or behind. It was a real eye opener for him in how much he actually spends. Now he'll eventually get his flyer when a short while ago he gave up on it.
The way I see it is you can get by with a slightly lower stats and be frugal. After you get your epics you can start gemming and enchanting with the more expensive stuff. You can easily spend 1k on gems and enchants on a single piece of gear. Imagine if you only spent half or 1/10th of that temporarily until you got your epic.
Epics are forever, gear will always get replaced. I don't think epics are necessary. I do believe their worth it.