Dang! I just realized that this debate was made 3 years ago.

I have been using both ANACS and PCGS for grading and have been very satisfied with their service (although not always pleased with the grades LOL!)  From my perspective they seem to be consistent on their grading and both have been very responsive to my questions/correspondence.  I did try to register with NGC both online and even with a paper application based on my ANA membership and never received any type of response or acknowledgement from them.  Perhaps I have been remiss in not calling them directly.  I don't see much difference in the slab types except for aesthetics, they all serve their fundamental purpose of protection from damage and collectable coins should still be maintained in a good storage environment.  I have purchased coins in NGC slabs and will probably do so in the future (buying the coin not the slab) but since I have been happy with PCGS and ANACS I'll probably not pursue another grading company.

NGC and ANACS for me. 

ANACS does many VAM and error varieties the other big two don't.

To word the topic "better" seems to bring up more about personal preference than consistency and accuracy based on the universal guidelines used to assign a specific grade. From my own past experience, both purchasing and comparing, I've drawn two distinct differences separating the top two graders NGC and PCGS. Coins which are bright in the higher grades or the natural look from circulation generally bear no clear winner as being "better". The real separation seems to be when grading earlier coins, and especially heavily toned coins such as proofs. When the latter is present, particularly deeper shades, PCGS has the slight edge. Or so the market place seems to reflect when it comes time to buy. With the bright coinage the gap is tighter.

What I haven't mentioned, which owes to the title, are the remainder of the grading firms. While ANACS, falling into this category where actual grade assignment becomes relaxed based on the standards, would come in a close at number three. If not for the volume of details graded they would be much more competitive to the top two. The remainder, not so much since on average their grades vary drastically by one to two points. In more cases than not, by a large margin. Has anyone received something back as "non-gradable"? 

Again, this is my own opinion based on past experience. Which to be clear only ensures that they are genuine  before cracking them out. From my view, grade takes a back seat to eye appeal every time. Which is why they are in much more pleasing round Air-Tite holders. Saves a ton of space as well.

With my VAM's that are raw or graded with no VAM attribution on the slab, I use VSS. He, Variety Slab Service, does not grade the coin. If itis raw he will put it in a Amos plastic slab and attribute it with his VAM sticker. If it is already slabbed, he will put his sticker on it with the VAM number and a brief description of it. Nice and inexpensive. He also does great photography of your coin.

@Numismatist X

Greco Roman's comment reminds me that NGC is the only service to slab ancients. 

NGC. Why they tested all three at the time. N.G.C. won hands down. So the Smithsonian put all our defeat and pattern coins in them. Good enough for me

I don't know which is best.  I have problems with both the details of the grading practices and the business practices of all grading services. 

But as a customer, I HATE having to wait 3 - 6 months to get my coin back.  I hate it and it is even worst for NGC and PCGS. 

I don't get what I want from any of them.  What I want is an AI identification of the coin in the slab and an association of the coin with the owners... which is me... that can be locked down.  If the coin would come back on the market, I could put out an alert becased on the idetification information of the slabber.  In orther worlds, I want the coin secured until I allow for it to be transfered to another, and I want the coins providence to follow with the coin.

They are worried about the slab being secured and grading for profit.  I am worried about the authetication and security of the actual coin, and proof that the coin was not stolen goods.

I thought they were in business to make money. Besides vivid was a hard hit. Graders working g 6 days a week. I'm not in a rush!