Hi bigrcee.
In my opinion, both the Epic and the iPhone 4 are seriously flawed phones- The Epic has ALWAYS BUGGY Samsung software on top of its slow Android updates and the GPS issues still seem to linger after (slow to market) updates.
Then there's the iPhone 4 with it's constantly cracking (I've seen many in person) back plate and antenna issues.
With that said go with the EVO since you're looking at 4G superphones. Big, solid, beautiful, and software so smooth my first grader can use it (A sibling has one.) This is not a case of fanboy-ism. My family and I have dealt with Samsung phones (notice I said dealt with) of all types and now all of us have either an HTC or a Palm phone and we just look back and laugh.
In summary:
1. EVO 4G
2. iPhone 4 (despite workable-ish flaws)
3. Epic 4G
(*Steps off soapbox*) Just trying to help
. Personally I'm going for the EVO or its successor.
->Interesting note: The Epic 4G finally received its 2.2 Froyo update today, the day of the official 2.3 Gingerbread announcement. Irony + failure.