If you go to the forums on john petrucci's website and search this topic, you'll find indepth discussions on the topic of economy vs. alternate. They're pretty much all shredders over there, but if that's what you're into, they won't steer you wrong!

Here's a link to a search I did there:

economy, alternate, picking search on johnpetrucci.com forums

Do some more snooping over there, and some more on the GT forums (it's come up a few times here as well), and I'm sure you can make an informed decision as to what's right for you. Perhaps it's both!