this looks to be a suckers' thread, as almost any opinion is going to be attacked.
I guess though there is some value in discussing brands in general instead of specific flashlights (which we do all the time).
I think those that like Fenix (like myself) have a lot of good sense on their side. Fenix is putting out many useful models that are updated very frequently, and often bring the latest LED tech at reasonable prices and in good quality, tough (waterproof, HA III, etc.) formfactors.
They don't seem to be afraid that their latest offering will cause trouble for their older offerings - a consideration I think for companies, like SF, that still put out a lot of very expensive, incan flashlights - they don't want their LEDs to be so good as to obliterate their lucrative incan sales (not to mention battery sales, since these are higher for incans!).
Often if you are wondering whether a new flashlight from any company is worthy of your hard earned money, the first thing you should do is compare it with a similar Fenix product to see how it matches up - the Fenix's are the benchmarks against which others are measured.
The Inovas and SF's are tough, well built lights, but maybe because their main customer seems to be hidebound bureaucracies, they take their time to introduce the latest tech (speaking about today, not a few years ago).
Streamlight actually is more innovative in my opinion than either Inova or SF. The great thing about Streamlight is that they think of a particular need and design a light around it. I have several of their specialty lights, one covers UV needs but also has a selectable normal light output, another has a very focused beam (the Survivor LED, designed for firefighters), etc.
Just now they've come out with the Sidewinder, which is light, tough polymer based, MOLLE design, and has one strong white LED plus 3 colored LEDs, all of which can be individually controlled to various intensities. (now, they don't tell you what kind the white LED is, and maybe it's not going to turn out to be the latest tech, but no doubt this can be a useful light).
So if I had to order I'd put Fenix and Streamlight on top, with SF and Inova later in the queue. Once you start thinking about specific needs and flashlights, of course, smaller production or semi-custom and custom lights enter the picture.