Yeah, not so much. Especially when considering epic gems.
The first time I had an epic gem drop, I was in a Heroic group with some old realm buddies of mine. We all saw the purple letters and reacted as expected. "Oooooh. Ahhhhh." It was the Potent Fire Opal, a spell damage and spell crit gem. Everyone but my Mage buddy and myself had passed, and we spent some time talking it over. The conversation went a little something like this.
Mage: Wow. That's pretty hot.
Me: Yeah, it's definitely nice. Do you need it?
Mage: I'm not sure. I am stocked with Potent Noble Topaz gems, and those only have 1 less Spell Damage and 1 less Spell Crit. Do you need it?
Me: It'd be nice, but I definitely don't NEED it. I'm completely happy with all the Potent Flame Spessarite gems I have. An extra 2 points will hardly matter.
Mage: lol, this is sad.
Me: What? That an epic gem is hardly an upgrade for a crafted green?
Mage: Pretty much.
Me: I can see how several of these may be slightly significant, but really, how often are we going to see someone with several?
Me: Exactly. I don't need it. You should take it for the crit since I'm an Affliction 'lock.
Mage: Sure, pawn it off on me so you can guilt me into taking a different epic.
We were sooo disappointed with what we had found. The gem, as is the case with most epic gems, is hardly "epic" in nature. Adding one point to a couple of stats compared to a regularly available blue gem is just not all that significant. And sadly to say, even after months and months of seeing and hearing similar perspectives on the matter, Bliz hasn't done much to make these items any better.
Kinda de-values purple text, if you ask me. Now give me a +20 Spell Damage gem and change my mind. ;)