While material preference might matter in your case try to stay away of over-priced coins, some are worth it while others not. AM advice was nice, if you like it you should get it, chances are you will earn profit versus fiat but due to crypto's nature one is always better holding crypto.
by overpriced coins you mean casascius coins and so on or gold coins for example? Sorry for probably totally noobie questions
I mean coins generaly that aren't like casascius first of it's kind and have a obvious over-pricing but that goes fom merchandising everywhere not crypto related only.
Like you know a OZ of silver is perhaps 20$ the coin is valued at 40$ after making it look stunning but don't go around selling it for 80, people will pay but I don't agree with that kind of overpricing.
While this scheme seemingly worked for silver didn't look that well for gold, and some are fighting to get a bit over spot.
I'm kinda fine with casascius, i love kialara can't say a thing they are quality and have everything so i'd say they worth their price, there's other coins that would get you (at current low price) 5-8 oz of silver for 1 single oz, while I do admit they look gorgeous but it's still a tenth of its silver worth and nothing compared to a kialara which are quite complex too.
Some even might be proven to have the keys compromised. (still uncertain how sol noctis will end they too damn good looking.)
This being said unless you really sure what you doing i would rather bet for DIY coins unless we talking leleana as example and you know it isn't a fake.
Look at satori, from 20$ a coin (pre fork) to round about 75$ or more nowadays, I loved these coins and i now almost regret giving them away, on a side note they are expensive now but at the same time not produced anymore so it kinda compensates.
I'm quite happy i found the same coins krogoth raffles for btc marketing purpose, way better than satoris lol.