The grading of coins has long been the difficult, yet enjoyable aspect of coin collecting that has confused and frustrated collectors from the beginning. Because the value of a coin is ultimately determined by the grade, grading has all too often become bogged down in the muck of "what is my coin worth?" rather than "what grade is my coin?". In fact, grading is all about the worth of a coin.
We now have a multitude of coin "grading" services available to help the unknowing collector or as the case has become, the investor. Unfortunately the same coin graded by different grading companies will result in different grades being assigned to the same coin. Nothing has changed.
So where does that leave you, the collector/investor who wants to buy and maybe sell a few coins for the fun or maybe the profit that can be obtained?
Coin grading, as it turns out really is more of an art than a science, so why get so worked up about it? Get a price guide that also has grading guidelines and to the best of your ability, grade your coins as you see them. To avoid the haggling, I developed a decimal number from 1-10, including tenths and wrote that number on my collection so no one would know what grade I graded them.
When it comes to buying or selling, use that same price guide (making sure it is up to date) and price your coins without grading them to the prospective buyers, letting them decide if the price you are asking is reasonable for the grade that they think they are. (On eBay, a close up picture of the obverse and reverse and sometimes the edge should do nicely to allow the prospective bidder decide how they grade the coin and therefore what it is worth to them. You do away with the need to return a coin because they do not agree with your grade.)
Do the same thing when buying. Don't pay attention to the grade the seller has put on the coin. Grade it by your standards and then price it by your guide. If the price looks reasonble, then make the purchase. The typical haggling over the grade goes away and everyone is happy.
Coin collecting is fun and creates many opportunities to make some lasting friendships. Don't let those prospects be ruined by arguments over grades! Enjoy the wonderful world of coin collecting!