I have tried some assets for some time now (about two-three months) and will add some experiences/facts/opinions here (note that I calculated the dividends per year but have the assets only for some months, so changes might be possible):

NXT assets:

1) I bought the GlideSec asset, and it seemed to have extraordinary dividends (about 250 % per year compared to the price I paid for it) - and it was of course too good to be true, so I received this one and only dividend (for a week of course, not a year!) and then the whole thing was abandoned by the "developer" and turned out to be a scam.

2) Atomic asset: No income with dividends so far, no selling for a higher price possible so far. Maybe later?

3) Coinomat and Coinomat1: At least there is something going on and this project is not about empty promises. Personally, I get around 11-13 % (per year) dividends. But on the other hand, the price sank down much more, so I would not be able to sell it without a bigger loss.

4) Freemarket: Not much going on there so far. No dividends so far. Price declined so far. So: a loss so far.

5) Liquid: One of the best assets so far as the dividend for me personally (taking my buy price) is about 20 % p.a. AND the value of the asset increased.

6) Pangea: No dividends and a price loss for me, so far.

Horizon (HZ) assets:
(As mentioned earlier, all HZ assets currently have the problem that buying an asset means giving up the safe 10 % interest you get when you just store them in your account)

7) AAssetHZ: No dividends so far, asset is still new but never heard of any sales. Still, there seems to be some fantasy in it, as I bought early and could sell for a higher price which still seems stable but shows no movements at all in the last weeks.

8 ) HZxchange: The asset description promises weekly payouts, but no dividends and a price loss so far. But the project is still new and showed at least some progress in that it started.

9) HZChronos: No dividends planned. I could buy early enough and even though there are no results from the project so far, it is still young and I could sell for a higher price and win something. Buying price is still higher than issuing price.

BURST assets:

10) ByteBank: Quite good dividend around 24 % p.a., and the asset issuer placed a re-buy order near the issuing price. Good. But on the other hand, the value of BURST dropped.

11) BdeBank: Almost the same as ByteBank, but available at smaller units and no buy wall, so, a lower sell price.

12) ByteEnt: My best asset so far: Dividend about 30 % p.a. (in relation to my buy price, that would mean ROI in around three years) AND value increased slightly. Unfortunately, there is still this problem with the decreased BURST coin value which annihilates the profits.

The biggest income seems to be possible with buying an asset cheap (in most of the cases this is possible when you buy early, when the asset is new and just issued) and sell it at a high price. The funny thing about that is, that this might not require a long time nor a successful or trusted asset. On the contrary, "serious" assets might keep a "good" price over a longer time, but not necessarily extraordinary profits. I have watched some assets with (so far) reliable dividends of more than 20 % per year without causing a high attention of buyers and therefore with sometimes even declining prices. Instead, for a good buy/sale-return it is more important that you profit from the "hype", even if the asset never proved its functionality and is essentially bullshit or just sleeping for an indefinite time. So don't wait too long and try to sell it while there is some hype and fantasy in the minds of the buyers. Note that this is just my observation, I am not promoting this!

Some/many assets seem to be really just crowdfunding projects where the profits for investors may or may not come very much later. In my opinion, from the investor's point of view there is absolutely no reason to buy them fast and early unless you want to help this crowdfunding or unless you are so early that you can sell the asset soon for a better price again. But they are not worthy of buying and holding in the long term view as there will come later opportunities to buy them (again) when and if they (ever) start realizing their project goals.

One thing to be careful about is also the currency/coin-system where the asset is located: It's of no use if your asset pays e.g. 10 percent dividends and the price also rises to 110 percent, but the coin goes down 50 % at the same time. A realistic example, see above.