The Tarani is easy to find in the Journeyman and Master's model. I own both and carry the Journeyman model everyday because I prefer the lighter weight. They were originally manufactured by Blade-Tech in the USA but the cost kept sales down somewhat and the two models went out of production for a short time. Blade-Tech is still involved in the manufacturing process but have found an overseas factory to make them under the 5.11 Tactical name. They also use this factory to make many knives under the current Blade-Tech name as well. I have had no issues at all with either my Journeyman or Master's model.
The Journeyman uses 154CM steel and the Master's uses S30V. Eventhough the Master's model is a little more expensive I still prefer the Journeyman. The locks are the same on both models. You can find both currently "in stock" at
www.knifeworks.com under the 5.11 section and the Master's model is currently "in stock" at
www.newgraham.com
The website for 5.11 Tactical is
http://www.511tactical.com/browse/Home/Law-Enforcement/Tactical-Knives/D/30000/P/1:100:10000:10600
I own the Mantis MK-1 and two Emerson k-bits. I have carried the Mantis many times but I would personally pick one out myself since I found that the framelocks do not always engage properly from one knife to another. It's not bad for the price. I also like the Emerson combat karambit and many feel that it is the best. I like it alot but I have never been a big fan of the wave opening feature .... but that's just me. Others swear by the wave. Other than that the Emerson is top notch!!
For the money the 5.11 Tactical Journeyman model is my personal preference. I am also anxious to see how the new Boker turns out. If you want to spend alot of money then there are many custom makers that make both folding and fixed blade karambits.
For now the only two real quality production folding versions I would trust my life with are the Emerson and 5.11 Tactical variants. I don't carry a folding karambit as a utility blade. I only carry mine as a back-up (just in case) self-defense blade. That's keeps the blade sharp. Karambits are not the easiest blades in the world to sharpen although the Spyderco Sharpmaker does a pretty good job. The Spyderco karambit was also a good model and very secure but sales were poor and it is no longer in production. The only gripe I had about it was the all steel frame construction. It was just too heavy to carry for me. You can still find them for sale here at Bladeforums and ebay on occasion. For other every day cutting tasks I carry another blade. The 5.11 Tactical Master's model in S30V seems to be much more difficult to sharpen than the 154CM found on the Journeyman model. (Or at least that has been my experience with the few that I have found used and tried to put a slightly sharper edge on)