I don't think it's strange to shoot 4x5 without a darkroom. I have done for quite a while, using a changing bag and daylight safe combi tank, then scanning or printing at a public darkroom. The darkroom costs me per hour so I never want to waste time there developing film. I'm proably never going to win an award or sell a print but I enjoy the process!
Bill - I've never used this contraption, it doesn't look more complicated than the combi tank and probably uses less chemicals. My two reel paterson is 500ml so if the three is 750ml or 800ml thats better than the litre in the combi. It would also be better if it empties quicker too.
I think things to look out for are lining up the sheets in those grooves, and not getting two sheets in one groove. I would also watch out for the edges of the plastic damaging the emulsion of the film, the grooves look like they overlap the sheet quite abit. Lately I found this happening in the combi with Adox 100 (which has a delicate emulsion) so I've had to calm down the agitation.
It looks like this uses the central column from the paterson tanks, presumably making it possible to turn the whole thing inside the tank using that little twist stick, it could be interesting to do this instead of inverting the whole tank.
Finally if you have to buy a paterson tank the financal advantage is quite a lot less, this £35 plus tank £30 is £65 only £20 more for combi, sorry thats UK money I'm not sure about comparison in the US. Althouh the paterson can be multi-tasked where the combi is pretty much sheet film only.
there's my thoughts, Andrew