You MAY be right about a "coin worth many thousands", but actually, in those cases I doubt very much that a slabbing will affect the value much if at all. It's lower value items where a slab - rightly or wrongly - can add so much value. As for constructive criticism: 1. Dave has already pointed out, TPG companies do make mistakes, and fakes have been noted. So much for a cast-iron guarantee. 2. Storage - for those of us who own nice mahogany cabinets with proper 'cut outs', the slab is a disaster area. They cannot be stored in any of the traditional coin storage media, and they take up a hell of a lot of room. 3. Photography - very difficult if not impossible to take a decent picture, which is essential if selling. 4. Insurance - I have my own database which not only has scans of every coin that is worth more than £15-£20, but - unlike a slab - has the date purchased, where from, how much paid, notes on any distinguishing features, etc etc. More use to an insurance assessor than a slab that's ... oh, gone! stolen! 5. Handling - yes, those of us who own nice coins actually DO like to handle them every now and again.. wearing cotton gloves.. holding and tilting to view in just the right light.. examining through a loupe for any unsuspected varieties.. A slab makes all of that difficult. As for preserving its condition, you only have to look at Royal Mint proof sets from the 1970s to see how well sealed coins are 'protected' - true, you can't scratch them, but they can tone UGLY. Those who like slabs will continue to sing their praises no doubt, but there is a majority against them in this forum at least. I have a somewhat love-hate relationship with slabs. On one hand, I will not buy a slabbed coin unseen, as even a high grade (assuming it has acutally been accurately assessed) is no guarantee of decent eye appeal. I always avoid coins with bad toning, (large) carbon spots, scratches in prominent positions, small edge knocks etc and these "defects" are not directly indicated by the grade. Secondly, I agree that slabs can inflate the price of the coin inside (especially if the grade is high)and the asking price can be unrealistically high. Hence I rarely buy slabbed coins. Slabs (e.g. those of CGS) can make examining the edge difficult but the NGC slabs are much better in this aspect. I also find that many people do bash the slabs a bit and even the holders of coins slabbed recently can pick up a lot of scracthes / marks which reduce the pleasure when viewing. Also I am a believer than vintage speciemen / proof coins should always be with their original boxes and I consider a coin to be "incomplete" otherwise. Having said that, I do confess that I have slabbed the high grade (UNC to GEF) coins that I particularly like. I don't do it for the grading but for protection. I do like to enjoy looking at these coins without worring about gloves, dust, accidentially dropping them or breathing too close to them. Many TPG companies do take photo of coins. CGS photos are generally not too bad as they were taken before slabbing. (But NGC photos taken after slabbings are pretty useless). With regard to coins toning ugly in slabs, I wonder why don't the TPG companies slab coins under an inert atmosphere? Slabbing in dry Argon (or even plain cheap nitrogen)will not result in silver toning assuming the slab is air tight.