those ngc slabbed coins are really nice to hold and looked it. with the certificate and whatnot, but if you are thinking to resell it, you may want to avoid it.
this is a story i read somewhere, it is about a collector who is trying to sell his slabbed coins. he brought it to a reputable buyer and this is what the buyer said regarding the slabbed coins. "i am going to take a small pen knife and make a hole on the side and get the coin out, and then i'll throw it on the scale and pay you for its weight".
so, if you are planning to invest in silver, avoid slabbed coins. if you like the design and all and is planning to just buy 1 or 2, then go ahead.
for me, investing in silver or gold for that matter is basically for the long run. no exit strategy (except for paper gold/silver. you have to lock in ur gains).
buy physical silver, store it somewhere safe and then go on with ur life. make your money the way you are making it now. if you got extra money, buy some more silver. 5-10 years down the road, then you can slowly think about ur exit strategy. if you are planning to make money in silver in a year or a few months, i would suggest you go into stocks (tricubes anyone?). silver is not about making money, it is about preserving money.
in the end, the best way to preserve money is to make money faster than inflation. how? well, it's easy.
1. make more money today than you did yesterday.
2. the next day, repeat 1.

If we hold physical silver/gold for long run like unit trust? Would we be in profit 5/10 years later on the road?