Hi,
As you have, no doubt, already searched this forum about this, you will have found my previous question on this topic. If not, you can find it here
//www.diynot.com/forums/viewtopic.php?t=29948&highlight=flueless
After careful consideration on the same question (including that stove), I rejected the flueless gas fire for the following reasons, notwithstanding the fact that some gas fitters will refuse to fit them, and some other are okay with them;
1) Although I felt that the combustion products (CO, CO2, etc) would be handled adequately by the catalytic converter, I felt that the condensation *would* be an issue. Having seen what my gas cooker, for example, can do in the kitchen when run for only a short time, the possible consequences of running a flueless for a whole afternoon or evening were a bit off-putting.
2) Even though all the thermal output goes to heat the room (when it is on), the thought of a permanent 100mm diameter vent with no baffles, was a bit too much. This ventilation is there ALL the time (or should be).
3) After many years with a balanced flue fire. I really wanted an open fuel bed. This is not possible with a flueless, since the combustion products must be passed through the cat, and therefore have a glass front.
In the end I settled for a power fan flue, like this one
http://www.verine.co.uk/quasar.html but with different styling, and faux coals. Even in the current cold snap, any reverse venting through the fan unit (from the outside), is not apparent.
HTH