Take a gander at the schematics for most of the amplifiers produced in the early to mid-1950s. The vast majority will look alike, largely because there are certain things you absolutely HAVE to do if you're using a 5Y3 rectifier tube, 6V6 output tuve and some sort of simple preamp. Indeed, many of the early designers took their designs straight out of what passed for application notes at the time (e.g., Radio Tube Handbook).
The same is largely true of many effects these days, whether they come from DOS, Daphon, Johnson, Behringer, and a truckload of other pedal-makers. Once you decide to make a chorus pedal, you're pretty much sucked into using the Matsushita (or currently the Cool Audio) chipset, a 2-opamp LFO, 3-4 poles of lowpass filtering built around a transistor before the delay chip and after, yaddah, yaddah, yaddah. In other words, while there is some room for small differences, design-wise these puppies are going to end up being VERY similar to each other. Take a look at a few dozen schematics for commercial phasers, flangers, and delays, and with very little exception, they will pretty much all use a single FET, switched with a 2-transistor flip-flop to lift the wet signal from a mixing stage and "cancel" the effect. For the most part, differences will be in build quality, chassis type, and perhaps feature set.
Again, I don't say this to slag these pedal-makers, any more than I would slag Fender, Gibson, Gretsch, and everyone else making a 5W Class A amp in 1954. Some aspects of the circuit are simply compelled by the nature of the circuit and core components, and it is hard for manufacturers to establish some sort of distinctive personality on top of that.
Indeed, the vast majority of pedals ARE currently manufactured in China. It IS one big friggin' country with a lot of skilled workers who can apply that skill for much less than North American workers. Moreover, while use of through-hole components and conventional PCBs is something that a guy can still do here in his basement, once you decide to make the move to surface-mount, that tends to push you towards approaching assembly facilities in Asia that can do that for you. You can pretty much bet that if a pedal costs less than $100, the chances are very good that it was made in China.
I've known designer RG Keen for over 15 years, and some comments he e-mailed me when production of the Visual Sound Workhorse amps started up in China were quite interesting. While stuffing circuit boards with high quality control was no problem whatsoever to the labourers there, with no real native rock culture, and little sense of what the amps were supposed to sound like to the ears of musicians, he found himself having to go over and tutor the folks building the amps on tone. That is, I suppose, yet one more reason why any use of Asian manufacturing facilities/labour tends to necessitate a fairly standardized approach to design; if you had to rely on tuning a circuit by ear, you'd be kind of stuck. Consequently, pedals made by Asian jobbers tend to be conservative in design, and the sort of thing a completely unmusical person can paint by numbers, so to speak. Not a sin, really. I can't imagine the legendary Abigail Ybarra is any sort of guitar slinger and tone-meister even though she winds/wound pickups for the greats, and I can't imagine everyone at Peavey in any of their southern plants who puts tolex on amps is a walking Bob Thiele either.
Incidentally, Asian jobbers that crank out pedals under different manufacturer names is far from a recent phenomenon. The Univox Superfuzz appeared under at least a half dozen manufacturer names that I know of, and even something as seemingly idiosyncratic as the Mutron envelope filter seems to have been produced under around a half-dozen licensed names. I had a "Funky Filter" (bought in 1978 for $25 from Pongetti Music in Hamilton) and had absolutely no
idea it was really a Mutron. http://filters.muziq.be/model/musitronics/mutron3
Finally, many of the review comments one sees about pedals tend to be based on the reviewer's experience with one copy of pedal X and one copy of pedal Y. In a world of 5% tolerance resistors and 10-20% tolerance caps, there can be more than enough variation in pedal performance that the reviewer may mistakenly be thinking that pedal X is noisier or more whatever than pedal Y, when they are really comparing an example of each. Though quality control has increased dramatically in the last 25 years (and you certainly would NOT have seen 1% resistors in anything made before 1980), there is still some pedal-to-pedal variation to be expected. Ironically, though you would think component tolerance, multiplied by the number of components used for a pedal would make the more complex designs more variable, it tends to be the case that the simplest designs (e.g., Fuzz Face derivatives) show more pedal-topedal variation, simply because in a simple design each component, and differences between them, matters.