Pretty safe to say (at least I hope it is considering the amount of research I've done in the past week on the Homebrew OCFD) that it's considered to be a somewhat good/somewhat mediocre performing antenna in general compared to actual tuned resonators but that's pretty much a given if you understand anything at all about antenna technology. For general purpose reception (not transmitting, obviously), the Homebrew OCFD will do "ok" across the given range which is commonly listed as from ~30 to ~800 MHz give or take a few - it's a very wideband antenna when built according to the wiki "standard" design.
Also pretty safe to say that the far far more knowledgeable folks about antenna design around here (hertzian, popnokick, etc) have stated multiple times across multiple posts in multiple threads that no, the Homebrew OFCD will not compare favorably against solid commercially available antennas of a similar nature aka wideband scanner reception antennas. Considering you can build a Homebrew OCFD for basically $10-20 and also that you can use it reasonably well inside a residence, in an attic, hanging in a window, and so on means you get an antenna that does work, maybe not to the levels the commercial ones can or actually do, it sure can't hurt to build one at some point and see just how well it performs for you.
I'm about to construct one myself here soon to see if I can improve upon my current situation which is basically SDR-centric reception these days using two RTL sticks, SDR# software, DSD+ (with DSD on occasion), Unitrunker, and the rather ubiquitous Radio Shack 800 MHz duckie along with the also rather ubiquitous Diamond RH-C77A dual band whip feeding into a cable attached to the RTL stick(s) using an MCX to BNC pigtail.
I'm located in a great spot in my area, in the center of most everything, with most of the major radio traffic taking place fired from repeaters that are on the mountain-tops that completely surround my area (I'm smack in the middle of it all, actually), up on the 3rd floor of my apartment building but but but.. I can't get an antenna on the roof so, I figure the Homebrew OCFD might help my situation given the reports by many other people that have built and continue to use them of how well they actually do work overall.
I suppose I should back up a bit with the "not as good as commercial hardware" line of thought and say that I'm stating that myself based on what I've seen the more knowledgeable folks say about the Homebrew OCFD. The consensus as I currently understand it is the Homebrew OCFD is way way better than any simple telescopic whip or duckie antenna included with most scanners so in that respect it's almost a must-build kinda thing for anyone (and considering the price, again, it's not like you're spending $100+ on it, regardless of whether you build the wire version, the copper pipe version, or one of the "shorty" variants).
I think it'll probably surprise me when I finally get around to building my own, at least I hope it will. Might build a second one, a "shorty" geared towards the MilAir band since I'm a few miles from Nellis AFB. I can barely get the ATIS from Nellis currently with the Diamond RH-C77A; I rigged up a cable to an SO-239 chassis jack and stuck a cut-to-300 MHz half-wave wire coat hanger homebrew and it makes a huge difference with the ATIS reception so I have high hopes for the Homebrew OCFD.
Can't hurt to build one, or two, or whatever I suppose.