The OCZ Vertex 2 3.5" form factor SSD is a story of equality for the desktop. For years now SSDs have been designed for notebooks and the desktop remained silent. Those days are over and the desktop has finally spoken up and OCZ heard the cries for lower access times and higher data transfer speeds.
In all seriousness, the OCZ Vertex 2 3.5" performs exactly like the 2.5" model, even with the different flash configuration. Going through the list of benchmarks, it's clear that the two drives are nearly interchangeable when it comes to both synthetic and real world performance. Yes, I am a bit surprised by this and was expecting something different, but it is what it is. The OCZ Vertex 2 3.5" drive has the same award winning performance as its 2.5" cousin does.
At the same time, the prices for both drives are exactly the same; 229.99 for the 120GB models at Newegg. The performance isn't going to change, but I think over time the price will. This is a strange time of year to look at e-tail pricing. The Christmas holiday has pricing bouncing all over the place with sale prices one day and inflated prices the next due to high demand. SSDs are on the top of many "computer guys" lists and OCZ's top notch marketing and high performance has led to the Vertex 2 being asked for by name more than any other SSD on the market. Once we get out of the holiday season we may see the 3.5" Vertex 2 and Agility 2 price decline slightly.
The real question for desktop users, though, is if the Vertex 2 3.5" drive is a proper fit for their systems. To answer that question you should really ask yourself what you plan to do with your drive after your next purchase. If the Vertex 2 is going to have a long term home in your desktop, then having the convenience of a native 3.5" install has a very positive outlook. If you are someone who will upgrade to the latest and greatest, possibly the Vertex 3 early next year, you might want to look at resale value or moving the Vertex 2 to your notebook.
I've said on many occasions that once you go with an SSD for your boot drive, you will never want to use a platter drive for anything. This goes for your notebook too, so even if you think one drive will do for now, you will want a SSD for your notebook sooner than you think. Because of that, the 2.5" drive might actually be a better buy at this time since the prices are identical and the 2.5" Vertex 2 ships with a desktop adapter. You lose the ease of installation of a 3.5" native install, but in the long term you set yourself up for SSD bliss all around.