One thing that impresses me about Calvinists, is that they are not apocalyptic, and they find real value in this life. They are very dedicated to serving Christ's interests on Earth, today. Often, this takes the form of doing good for others, by means of education and charity.
A lot of people preach the gospel as "You better straighten up because the world is going to end" when it's supposed to be: "We are sinners and deserve to be punished. Good news is Jesus died to pay the penalty for those sins so that you can enter into heaven."
Reminds me of Galations 1: 9 As we said before, so say I now again, if any man preach any other gospel unto you than that ye have received, let him be accursed.
Also, we are usually believe in covenant and post millineal theology where the apocalyptic denominations believe in dispensationalism - That means that where people like JWs believe in a 1st and 2nd fulfillment of the prophesies, we believe it was prophesied and fulfilled .. period. No 2nd fulfillment. We believe we are in the millineum now and just waiting for the end/2nd coming. There isn't as much debating about the mark of the beast and so forth. (And I'm totally not an expert on this subject - If I have a detail messed up, don't slaughter me!)