Like the OP my wife and I had only flown economy until last year whan we returned from Vegas (LAS) to GSO (Greensboro) thru CLT (Charlotte). The flight from LAS to CLT is 4 1/2 hrs but only felt like 2 hrs in first class. We redeemed United miles for the US Airways fights--the best way for us to get a US flight.

That spoiled us! We have upcoming first class flights to LAS on Delta returning from SAN (San Diego) The long flights thru ATL (Atlanta) will seem much shorter in first class. We are also returning from PHX (Phoenix) on a subsequent trip using United miles for a US Air flight thru CLT. We will be flying to ABQ on the outbound flight in AA economy. There is no reason to get first on this flight since the ER4 on American only has one cabin. We actually have to pay first class miles on the ER4 or fly thru Miami.