Would it be more wise to use an OWC SSD and install it myself or go with the Apple option for more money without voiding warranty?
Is the Apple SSD a 3G or 6G speed?
The OEM Apple drives are SATA II (3G). Unless you are doing a lot of work with very large files, such as video editing, you will not likely notice the speed difference in day to day usage.
As you said, the internal drive on an iMac is not a user serviceable part, so you do create warranty issues. Watch some videos of how this is done and you will see it is not for the feint of heart. If you want to risk breaking your new iMac to save a little money, that is up to you to decide.
OWC uses Sandforce controllers in their drives and Sandforce based drives have not been the most compatible/reliable. Each new generation of controller Sandforce comes out with seems to take months of firmware updates to get it stable. If you do install your own SSD, I would go with either a Samsung 830 or Crucial M4. Read over the main
SSD thread for others opinions on this.
First, the OWC SSD will outperform the Apple SSD. Second, the OWC SSD will not lose speed over time. Third, if you are concerned about warranty, with a new machine, OWC has a warranty program that either coincides with Apple's over supercedes it. They have a turnkey program. You ship the machine to them and they do the work. If the machine is new, you can have it direct shipped from Apple to them and they send you the computer when the modifications are done. There are quite a few additional internal options available in addition to an SSD including: an additional hard drive, a second SSD and an eSATA port. Check this out:
http://eshop.macsales.com/shop/turnkey/iMac
You comment implies the Apple OEM drive will lose speed over time, and this is wrong. Apple OEM SSDs support TRIM and will not lose speed over time.
As you said, the OWC upgrade program coincides with the Apple warranty. So what do you do on a Thursday afternoon when your new iMac will not work? You sure can't just walk into the Apple Store with it to get it fixed now with that OWC SSD patched inside.
OP>> If this is a hobby for you and you want to take the risk to save some money, have at it... but understand if this computer is for business or serious work you need to depend on, you are really out on a limb is things don't go well.