Seems Like Decent Quality with Only a 2 Amp Fuse
597787
I used this to replace the Male lead on a 12 Volt Kooltron electric car cooler.  Both the male and the female parts on the cooler needed replacement.  Being very careful to match the center lead on the original gear with the center lead on this replacement things seemed to go fine.  When I plugged it in the cooler quickly started and died.  I found a blown 2 amp fuse inside the plug (unscrew the tip to reveal the fuse).  My cooler transformer puts out 12 volts at 5 amps.  A quick trip to the auto parts store found a box of 5 fuses rated at 5 amps for $3.50.  I swapped out the blown 2 amp for the new 5 amp and everything works fine.
Others have complained that the plug is loose in their cars.  I found that the plug has a very good fit in both my Honda Pilot and my Honda CRV cigarette lighter plugs.  The fit in the replacement female socket on the AC/DC transformer is also very good.  The green LED on the Roadpro Plug lets me know I have a good connection.
4850546
Blows fuses, can not buy the fuses locally, but other than that when it works it does exactly as I need it to do
3817015
It works as designed to add a electrical system to the existing fuse box. I just wished they would throw in 2 fuses with the price. LOL
3258708
I needed a real short cable to connect a small 200w amp below my new head unit. This one is long enough to do that without any extra cable to spare! The fit was a little loose so I'll have to keep an eye on that.
4004117
It fit, and it seems like decent quality but time will tell. The reason for only three stars is because the wiring harness is not the same as the OEM unit; it does not include the protection diode that is in the OEM harness (hidden underneath the protective flexible loom). The purpose of this diode is to protect the electronics from the back voltage spike that occurs when the clutch disengages and the magnetic field collapses. I wasn't comfortable with this so I cut off the old harness, diode and connector and soldered them on the new unit. I shouldn't have had to do this. Maybe this diode is buried within the new coil itself, but it was not stated anywhere so for safety reasons I must assume it isn't or risk having to buy a new ECM when it takes the hit and dies.
2435374
So far they seem great. I've used one to power low powered item and wanted to tap into fuse easily and this worked out perfectly.

I wouldn't advise this for higher powered items. Some of these have bad build quality just inspect before installing as you may have some duds.
1853903
Easy to install, works as advertised, only issue is that it did not come with the mini 20 A fuse.
2783711
This unit is uses a hard-to-find micro fuse (I assume is 10A). The socket will not fit into a round hole, unless the hole is notched.

(I have one of these tiny fuses in a VOM for the amp meter. Sears, Home Depot, Lowes, Ace Hardware, AutoZone, and RadioShack didn't have a replacement fuse). Maybe they carry them now..?.

This looks like a light duty device. It has large holes in it's sides that could allow a loose screw or wire to get inside,
and come in contact with the center connector, +12V.. Which would blow out your rare fuse.

I wanted this socket to use in a portable 12VDC power supply, but now I'm thinking of using something from RadioShack.
1953177
Installation was easy.  Have had about 2 mths and all is fine.  I am not sure if I have had very many surges in that amount of time but all electrical components continue to work fine.
187421
I am definitely not a car guy, but this worked great. The included fuse for the new circuit is 5A. It would have helped to know how easy it would be to attach the other end for the new circuit; it is an auto style butt connector which you crimp.  I crimped too hard (I know, pliers are not crimpers) and cut the wire, so I used my preferred method of solder and shrink wrap. Check your fuse type first as there are a few types.  I used this one on my new Honda for a permanent dashcam.
2523642
Not used yet but good quality components and wiring
1158688
Worked well to connect 2 batteries together in my powerhub 1800 box. Seems to be decent quality.
2786599
I bought this to power my CB radio, and while the radio should probably not pull enough juice to blow a 2 amp fuse, it is very troubling that they would put such a low amperage (and supposedly non-standard sized) fuse in a unit with 16 GA wire; that is ridiculous.

So in fairness, it works for me - and the rest of the unit  is of much better quality than the Autocraft branded piece of trash I bought at AutoZone, but the fuse issue can't be ignored as it is simply very poor design.
2285398
Powers my Goluk T3 without issue.  My only problem was the add-a-fuse was bad.  Confirmed by moving my existing add-a-fuse to the new location.  Oh, well.  I mainly bought this for the 5v wiring anyway.

Edit:  Just read a review by Jay about filling the slots with a fuse.  I guess I'll have to buy a fuse and test out their theory.  However, if that works, my 4 star review will remain unchanged.
3701259
I haven't fully installed the system yet, but this thing looks like quality. I especially like how small the fuse block is in relation to having 4 fused outs. Can't wait to complete the install and show it off.
3882377
These seem pretty well made, and for the price, are a super bargain.  The quality is good, but the cap that covers the fuse doesn't snap on as tightly as on some other fuse holders I've used, that really snap on tight, and give the impression of being better sealed to the elements.  However, they also cost several times as much, so unless you need super-premium quality, these are a very good compromise between price and quality.  Again, not super-premium, but far from junk.
327078
Build quality: all metal chassis, very compact, seems like good quality connectors and LEDs.

Functionality: Works as advertised,  I have 2 on my board.  The outputs are isolated... I have combined the 12V from my 2 to create a 24V for one of my pedals (Voodoo Labs sells the cable).  I haven't tried combining in parallel for more current so I can't guarantee that.  I also haven't tried putting the outputs into overcurrent, but they are supposedly individually short circuit protected.

Value: For the price, a no brainer.  A fraction of the cost of the popular brands.

Pretty pathetic documentation, but I'll accept that for a good deal.