Not exactly. The old JMicron 'FIXED' controller is generally referred to the JMF602B or the slightly 'more-FIXED' JMF602D with 64KB of cache. The first gen SSDNow V (SNV125) used the JMF602D controller.
The second gen SSDNow V (SNV425) uses a Toshiba branded controller although it has been suggested that it is based on the JMicron JMF618 design. The SNV425 has a 64MB DRAM chip which is most likely used to cache data.
As for the performance of the SNV425, it is certainly not as fast as the Indilinx or the Intel G2. Its claim to fame is price and IMO its place in the market is a boot/apps drive for users who want something faster than a VelociRaptor but can't justify the comparatively high price of an Indilinx or Intel G2 drive.
To quote Pure Overclock in their SNV425 review:
Frankly, we often look at performance as the primary consideration when reviewing products but this is a glaring exception; price is driving this Kingston SSD, and the price is excellent for what you get.
To recap the performance, then, let's break it down summarily now. The short version is the SNV425-S2 cannot compete with the Indilinx-based SSDs. However, that's not to say this drive isn't fast, because it is. Will you notice the difference? Perhaps, perhaps not. But the reality is that compared to your traditional hard drive, this SSD is stinking fast.
Additionally if you're not a heavy multi-tasker, the difference between this budget SSD and a more expensive/faster SSD might not be that noticeable. To quote another review (this time LegitReviews):
In closing, I'd like to share that my main system is running on a 128GB Patriot Torqx which has higher read/write specifications than the Kingston. Using the bundled Acronis software, I cloned my daily Windows 7 instance over onto the Kingston and used it for several days, performing my regular activities. I saw little, if any, difference in performance and was pleased with how smoothly it performed. All in all, Kingston has done a very nice job of tweaking their V Series drives for the better and just like the first generation, we think it's deserving of the Legit Reviews Value award!
Disclaimer: I bought the Kingston SNV425 a few weeks ago although this was done after *A LOT* of research.