Should you do this? It depends on your coin. I believe it's fairly expensive to send the coins in so unless the value of the coin exceeds the price of the grading submission then it's probably better not to send it in.
There are many who, like yourself, do not like the "cases" or slabs. They prefer to be able to physically hold their coin. However, coins in slabs carry a premium. You can take the coin out of the slab but then your coin looses that premium and it's assured grade.
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You make some good points. One thing the well known grading companies do is to certify that a coin is not a counterfeit. I bought a small collection the other day at a fixed price per coin (by denomination of course) and there was a 1894
Morgan dollar in it. It looks and feel real, and the weight is where it should be. However, if I decide to sell it then it would probably be in my best interest to have it certified by PCGS or NGC to get the maximum dollar for it.
Like you and the original poster, I dont care for slabbed coins a whole lot. They take up alot of room and I dont need a coin grading company to tell me what the grade is in most instances (some coins I need more practice with the grading but I have a pretty good idea on it).
For the original poster, if you were to send in some coins to be graded and your goal is to maximize your return, you are best off going with PCGS or NGC since they carry the highest premiums in the eyes of collectors. Stay away from the cheaper, lesser known grading companies as the money you will save up front on the grading costs will be offset by the smaller dollar amounts you would get for your coins. Good luck!