If I had more time or more knowledge about what I was looking for I think I could have found a clone of this device for nearly half the price.

Having said that, this purchase was worth it. This tool does more than just read/report the error codes from your vehicle, but it is still very easy to use. I had no problems using it and it worked out of the box. It had a decent amount of storage too! I was able to recored my vehicle operating under various scenarios and save that information for comparison later.

You need access to a computer with a Windows operating system to update the tool. I just updated mine. Same goes for printing or moving that data from the device onto a computer. I think that is pretty standard for these type of devices though. If you aren't computer savvy and don't care about this functionality, then you can just ignore it. The device, and all of its diagnostic features, worked perfectly straight out of the box.

This scanner is extremely easy to use. I had an Engine Check light on my 2002 Toyota Tundra. Connected my Konnwei OBDII KW850 for the first time out of the box, red the code which was pointing at the Emission Control "PWM-Vacuum Switching Valve". Located the valve by looking at the Vacuum Hose Routing Diagram (under the hood) and realized the vacuum hose to PWM-Vacum Switching Valve was disconnected by itself (for some reason manufacturer didn't put a clamp it). Plug it back in and reset it by using my OBDII Scanner and there it was the engine light went off. I forgot to mention that my inspection was running out and I thought I had to spend tones of money on mechanic to get it fixed but this scanner did the trick. This scanner is definitely for Do it Yourselfers/DIY.

I liked the feel of it, its big, good grip.
Options are reasonable for what you pay, the programming seems solid.

My only hang-up is the housing, okay, but seems like sorta cheap plastic with a removable rubber outliner. Not Waterproof, so be careful around wet areas.
The PC software might need a bit of polishing, but okay I guess, considering you'll only use it for updates, data viewing and printouts.

Now what I did with it first think I got it:
First, I updated the first one (Black KW850), everything went well.
Then I went on to update the second one (Red KW850), now this one it didn't pick up, so I contacted customer service through email. They responded rather quickly and they helped extensively.

Red KW850 came out of box with firmware Ver: 4.1, could not connect to software to search updates. It recognized, just didn't give the option for a search or at least a display "latest firmware installed", something.
Black KW850 came out of box with firmware Ver: 2.1, the software updated it to Ver: 3.2, took 5 minutes done.

Now I've tried to get it connect, it sees it, but the update button doesn't highlight to do a search.

Now I've asked the rep about it and if I should be concerned  about it.
They told me I really shouldn't, the programming is pretty set and usually the updates are pretty small and few/far in-between. Most of the time the updates are mostly language related, like if they add a language for foreign use. But other than that it works Fairley well, at least just for personal use and maybe quick/easy professional use.

So bottom line:
good product, solid OBD2 programming, decent enough PC software (bit of work needed), housing okay (could be better w/added Waterproofing), solid OBD2 cable, comes with storage bag (thats a plus), pretty good manual (clear cut instructions & explanations). All in all, im good with it, for the price.

Just so whoever reads this, Version's:
Konnwei OBD2 KW850
KW850 Professional
KW860
KW870 w/ direct battery adapter cable (Unavailable on Amazon)

Outstanding product, at the price Amazon sells this item for you would have to pay $35-$50 more to get a Unit from your local auto parts store that has the same features, I was lucky that Amazon offered a coupon with my purchase that made it an even better deal

Got the unit, followed the straightforward instructions, did the online update, and then used the unit, it did everything it was supposed to

For those with older car some of the diagnostic tests might not work on your car because the CAR MANUFACTURER won't allow it, that is not KONNWEI's fault, on newer cars those tests will work

In summary, when you do a price vs performance analysis on this unit, the KW850 is a great deal for an OBD2 scanner

Was nice display powered by vehicles serial port. The device was pointing to exact problems an older device did but this one is nicer given active testing, o2sensor, misfires, error codes, testing, readings, engine temp extra which doesn't come on old or super cheap models which only give error codes possibly reset engine light. Also this appears to have no pay to use software as I also seen scam devices try bait low price device then go for software fee. this is reason I am not only keeping this but recommending this since it is what it claims to be. I like the fact gave me probably everything the onboard computer for 2000 Chevy blazer knows. Which is way more than I thought cpu knew in 2000 cpu prior to this tool giving me more confidence in targeting mechanical problems and ignoring other costly mistakes, if vehicle is passing tests.