I couldn't agree more with a lot of the posters here. I too collect both and at best I'll break even with all the numi purchases I've made from colored, to gilded, to 'reg' numi coins primarily from the Perth Mint. On some I lost a lost DD snake, and on others, 5 oz Niue gilded lunar horse I made a killing (on paper, and if it can sell). But I'd say generally speak the numismatic coins are not worth it (the modern ones). UNLESS, one is collecting to admire a piece of art and not necessarily focused on the investment value per se.
Heck, there are colored coins I do like to look at (Funnel Spider, Santa Maria great ship, Red Whelsh dragon, etc...), and bought them sorta knowing I wasn't going to see a huge return (no return, maybe a loss), especially when paying 160.00 for some. Just think how many kooks I could have bought with the 160.00, and over time those 5 kooks will perform much better than the 1 redwhelsh dragon, IMHO.
So, unless your a speculator or appreciate fine art (beauty is in the eye of the beholder), then I'd stay away from these modern collectibles. Another example is the Spider man series coin from APMEX. I bought 2 of the COA, with actual signature from Stan Lee. It wasn't cheap. About 569.00 to be exact. Will I get my money back, make money, break even? Who knows. But for me, every once a and a while it's fun to roll the dice. I figured Stan Lee is 91, and when he is gone, maybe this will go up in value, since there are only 25 of them. Who knows though. But I WENT INTO IT knowing it was a gamble, and that's okay.
On the flip, I only stack semi-numi silver (kooks, kolas, pandas, and lunars). I like these because for the most part you can buy these for the same price (a little more) as a silver eagle, but there aren't 40 million minted in a year, and the design changes every year, and if one year is a home run, and a new collector wants to collect the whole set, well, they are going to pay a pretty penny to get some of the older years to complete the set, as they have extremely limited mintage numbers (kooks, koalas). I do not stack rounds or mega minted coins (ASE's, maples, philharmonics, etc...), and ones that stay the same year after year...
My two cents.