I have the Intronix LogicPort and the ZeroPlus and greatly prefer the LogicPort.
The ZeroPlus has typical Made In Taiwan software which is to say it's pretty rough, a bit buggy, and not always intuitive. It's also hugely bloated--it's a 55 MB download. And it doesn't run well on a slow PC or netbook. The only real plus is it's really cheap.
The LogicPort has great software, is easy to use, and both the software and hardware have been bullet proof. It even works flawlessly even on a very slow low-end Intel Atom powered netbook. The software is 1/10 the size of the Zeroplus software yet is far superior. The downside it is only has 2K sample depth, and while the compression works well, that can still be a problem when you need to capture longer periods at high resolution.
Tech Tools has been around a long time, they're a USA company, and while I wasn't too impressed with the value of their older DV1-100, the new DV3100 looks to be a great product. I've run the software in demo mode and it's very user friendly (and 1/5 the size of Zeroplus). With 512K per channel of sample memory and what's probably the among the best compression out there, it should be able to capture nearly anything as long as 10nS resolution is sufficient. Plus it has even more advanced trigger options.
I'm likely going to dump both the LogicPort and the Zeroplus and upgrade to the DV3100. I *might* keep the LogicPort around at it has 2ns (500Mhz) resolution and I'm not sure how well the DV3100 will work on a netbook. But the Zeroplus is going on eBay.