Newbie Question: Which TPG Slabs To Collect?

I'm not sure which TPG does better with Kennedys, but to start I would compare NGC against PCGS as far as populations for the various grades, and what the current sale prices are for the various years/grades, and that should tell you which is currently "better" to collect. Someone else might just know the answer, but that's how I would go about evaluating it.

Buy The Coin; Not The Slab !!

Just remember, buy the coin, not the slab.

Also consider, if you are buying mostly online, PCGS has a shopping site for their registry sets (you can probably use the Kennedy half set) where they compile PCGS graded coins of that set for you to find easily. I find it very convenient to compare and find good prices.
http://www.pcgs.com/shop/sets

My answer is that you should collect neither. You first need to decide from a quality standpoint what condition is acceptable to you. Not based on the grade on a slab, but based on you looking at the coins yourself. Look at plenty of raw coins in the series to get a good idea of what's available at what price. You'll be able to determine the conditions that fit your budget. Coins sometimes need to be purchased in slabs because they need to be authenticated or because of their value. However, many coins are slabbed with the only real result being that the 3rd party grading services and dealers make more money. I certainly don't fault them for it as the purpose of their businesses is to make money, but with a series like Kennedy halves, you'll likely spend much more getting them in slabs for no real gain. I personally like having my coins in airtight holders versus slabs. It just feels more like I'm holding the coin. If you just absolutely insist on slabs, consider the do it yourself slabs. Remember, it's not what condition someone else thinks the coin is in that matters. It's the condition that you think it's in that matters.

PCGS might be grade more conservative with a particular series, and likewise NGC. That's why I suggested doing some research. I've seen instances where the market value of a particular NGC coin/grade will be x, and the same coin/grade in a PCGS holder will be 2x. Bottom line: Just know what you are buying before you buy it.

As others have stated it can vary by series but just looking at the graded populations it looks like PCGS has graded more than NGC. You can do some comparing here:

http://www.pcgs.com/pop/detail.aspx?c=125&p=MS&t=4

http://www.ngccoin.com/coin-census/...-page-0-base

All that really means is there's likely a larger supply so you may have an easier time finding ones you like with PCGS. Also as coinlover168 mentioned if you go PCGS they have a great tool for finding coins that are for sale at fixed prices on dealer's sites, at auctions and on ebay.

One other thing you might at least want to consider is not limiting yourself to one or the other. You say you'd like them to match and I understand that. Perhaps you could consider coins from all 4 of the main trusted TPG companies (PCGS, NGC, ANACS & ICG) and focus on the coin itself and then crack it out. This would give you the comfort of feeling secure that the grades are mostly consistent. Once out of the holders you can have them look uniform by either putting in a nice album (perhaps Dansco or Intercept). You could also go the airtight way that Bret mentioned. But this would keep you from being limited to only a portion of the coins that are out there and still give you the comfort you desire from buying a TPG slabbed coin.

I'm not sure I'd recommend that method with more expensive coins but with the Kennedy series it would make a lot of sense in my opinion.

It is critical that you develop your own grading standards for any series you collect so that you can apply them objectively against slabs you are looking at. As good and consistent as they usually are, PCGS and NGC often run counter to my experience with a similar coin graded the same way. Tell yourself you will not buy a coin, even slabbed, if it doesn's meet your own standard. You will not regret it.