I have been playing this on Free Play for the CM comp, and ever since release pretty much daily on LeoVegas in real play..
I can now safely say i have done a sufficient number of spins to confirm what i initially felt when i tested it first.
This could be an amazing game for wagering purposes, the bigger the bonus the better in this case. It's surprisingly friendly, and can easily recover from longer dry spells - in both feature and base. There's sniff of the 'ole Rhino in the basegame, when you get all four 3x multipliers, or even more (so that you could have 3x, 6x, 3x, 6x for example, which can pay pretty damn well, even without the grapes

), and the biggest hit i've seen without a 3x wild, was around 300x bet. That is of course nice to hit in the feature, with any multiplier, and even though it will not often retrigger more than once - there's still insane potential, with those kind of numbers.
I'm not saying you can't lose a bankroll on it, but it's definitely one of the most easygoing slots i have played in the last 10 years, and i've played tons.
I would stress that it's not a slot to highroll on: when you keep the bets to a minimum (average of 400x bankroll should be a 'safe' entry) but of course you can always go for a quick hit or whatever floats your boat. It's definitely an interesting slot, and i would most likely not have learned this without the incentive to hammer it for days during the freeplay comp..
So, my tip: give this a proper go, and it's volatility may surprise you..