Nice looking shutter system. It will provide good manual control but as others have noted, always blocks some flow and can have a bad failure mode. For those moving from a "traditional" RV with a similar system or a complex airplane with cowl flaps, this is a good choice.
Tape is cheap and effective, but is not controllable from cockpit, looks like **** and doesn't help warm up time that much. Did I mention that its cheap? Down side is that dumb pilots sometimes forget to take the tape off when a warm spell hits, then are surprised when the oil temp hits 240 on climb out. Not that this ever happened to me....
Oil thermostat is great for minimizing warm up time, requires no manual control (no forgetting to take the tape off when it warms up), but is expensive and harder to install. Highly recommended by many Rotax shops and very common on some S-LSAs.
There is no perfect solution. For those living in areas where it rarely freezes, tape probably works best. Outside that, thermostat or shutter, depending on whether you want to do it yourself or have the thermostat do it for you.
Doug "The Other Doug Reeves" Reeves
CTSW N621CT - SOLD but not forgotten
Home Bases LBX, BZN