well of course some dvds are worse then others,
if you want a cheasy ameri dubbed anime then the official ones are usually only ever in disks with about 3 episodes on each and cost around £20 each. Some of us however cannt affour over £100 to watch a series, so what fake dvds do you have to be aware of? well all of them, there illigal and fraud.
     But if you insist on buying them then the perfect collection boxes with a good presentation box are usually the ones to go for.
    Check out what the sellers returns poilcy is before you buy it, if they wont accept returns, dont even bother.
    Try to aviod dvds that are fake and not in a perfect collection as chances are there a cheap home made version thats been burnt quickly.
    many fake dvds are brought out by "anime studio inc" and you can tell if there fake as they have the hong hong email address on the back
    If you are not buying a dubbed anime then you should look for a profesional seller as many subtitled films are badly done, often getting names, places, date ect mixed up.
     Also check out past feedback about the box set your about to buy as chances are theyve sold one the same or similar in the past.
    If you have the money to buy a real copy of the anime i suggest you do so, as it is much better quality, however having bought many perfect collections i must say only 1 has ever been faulty, and even then only for 1 eppisode.
Just be weary and check out the returns policy, if they are paypal varified and all manner of things before buying.