ASUS just about pulled off an amazing SSD, but fell short with this one. The presentation is great, the concept solid, but the execution, as well as the price, didn't hit their marks. The Marvell RAID controller used in the ROG RAIDR Express passes the TRIM command, one of only two SATA RAID parts that I'm aware of that work. ASUS chose the Marvell solution because the Intel PCH is a chipset, and is not available for an add-on card.
The problem with the Marvell controller is it's not as fast as the Intel PCH found on most modern motherboards. The other problem is the Intel PCH is on most motherboards. For that matter, the Marvell 88SE9230 is also on many of the new enthusiast class boards as well.
If you have a newer Intel motherboard, anything after the X58, then you already have RAID TRIM, and it's faster than the Marvell controller. The ASUS ROG RAIDR Express costs more than two 2.5" 128GB SSDs, and even more than a single 256GB SSD. If you're looking for performance, two drives on the PCH will be faster, and cheaper.
If you're looking for a SSD to match your ROG motherboard, ROG video card, and color RAM, then the RAIDR is a good fit. The drive also has a number of interesting features that increase its appeal, if you are looking for those specific features.
One such feature is the hybrid option where the ROG RAIDR acts as cache for a HDD. At 240GB, the RAIDR is a large cache drive. Paired with a large HDD, the configuration would be impressive for general use computing, gaming, and other daily activities.
As a standalone SSD, the ASUS ROG RAIDR Express is an average SSD with a few bells and whistles, but the price can't be justified. If ASUS would have made a 480GB model, then the outcome would have been much different. Single 240GB SandForce controlled drives are quite a bit faster than the 120GB models. Two 240GB drives making a RAIDR 480GB would have been quite a bit faster than a single 480GB 2.5" SSD.