I'm a FIKI Bravo driver, it does what it says in the tin. Pretty much agree with everything said above, with a couple of additions/corrections:
Mooney do FIKI or no hazard as factory or aftermarket install. Principle differences are the twin pumps and heated stall vane, but you still would find it prohibitively expensive to change a no hazard system into a FIKI. The Bravo already has twin batteries and alternators before you put the TKS system on, I have a feeling the Ov only has one alternator as standard (but twin batteries)
General consensus over at PPL/IR when I was looking was that a turbo is more use than FIKI, and oxygen is required for either, although portable will obviously be adequate for the latter.
I would guess I do about 10litres of TKS fluid a year just keeping the panels wet, and for other maintenance the filters are a 2 year replacement item and an extortionate price (several hundred Euros). On the positive side, cleaning leading edges becomes a thing of the past, but for the rest of aircraft cleaning it is a six and two threes. It will drip on your hangar floor though, not a problem if it is permeable, but very slippery if it is sealed and painted
I can get longer than the 2.5 hours from a 6US gallon tank by modulating the use of it (not that I'd spend 2.5 hours continuously in icing conditions anyway) but it depends on the severity of the conditions. It's probably possible to blow the whole lot in an hour and a half if you don't choose your levels wisely or pay attention to the conditions outside. If I'm going away for 10+hours of flying, or 5+ in particularly nasty weather, I'll probably put a couple of 5 litre containers of fluid in the baggage bay, but have rarely dipped into them other than to top the tanks. I normally keep 20-100 litres in the hangar as you won't find it at every airport (It's not too bad to get, oxygen is harder) 10EUR/litre is the average retail price
With FIKI TKS the Mooney/Bo (and probably the others) become pretty much as good as you're going to get in the SEP as a 'go anywhere/anytime' mount, subject to your departure & destination airports which then become the limiting factor (my homebase has no snow clearing capability, it closes when it gets to 6" deep). The Mooney load carrying is rather poor when compared with the Bo, which is better in this respect, albeit with a small speed penalty. The CAV website at
Welcome - CAV Aerospace, Inc. has some more info on TKS