I've used Havelock since the beginning and over time I've spread my investments across multiple stocks. The one which to date seems to be most stable, credible and durable is B.MINE. With difficulty having massively slowed down in recent months, this is more than ever a decent investment.
Wherever you decide to invest, my advice is to spend quality time reading very well all of the Ts & Cs, understanding exactly what these companies provide. My experience told me that even the most credible business plans can easily go belly up in no time.
Overall, as per all Bitcoin based investments, I still wouldn'tt recommend investing anything you can't afford to loose. All of these investments remain high risk as noone can really predict what the future holds.
What worries me the most at the moment is the fact that I'm unable to withdraw anything from Havelock and hoping to hear from anybody who's going through a similar situation.