There's a big difference between using consumer grade MLC flash and running a very high intensity workload and using enterprise grade SLC flash and only using 80 MB/s of bandwidth.
As a consumer you really don't have to worry about write endurance, though. I mean, how much do you write to your drive every day, maybe 5 GB at most? Even with MLC flash and a fairly small 120 GB drive that'll last you for a couple of hundred years. And even when it fails you can still read the data out, you just can't write new data. The problem you should worry about is a firmware bug in the part of the drive that handles the wear leveling abstraction. I haven't seen one of those in a while, but when many companies were just starting to develop SSDs they occurred fairly frequently, though usually the manufacturer would figure out the problem and patch the firmware for new drives after enough failures in the field.
I actually think the best approach, longterm, would be to use the SSD as a cache for the HD at a filesystem level. I believe something along those lines was just merged into the Linux kernel.
If the SSD part fails you pretty much lost all benefit of the HDD itself. It might or might not function with the bad flash chips but you definitely lost all the performance boost. The caching options sound much better overall but they do take more space (2 slots vs. 1 for the hybrid).
As a consumer you really don't have to worry about write endurance, though. I mean, how much do you write to your drive every day, maybe 5 GB at most? Even with MLC flash and a fairly small 120 GB drive that'll last you for a couple of hundred years. And even when it fails you can still read the data out, you just can't write new data. The problem you should worry about is a firmware bug in the part of the drive that handles the wear leveling abstraction. I haven't seen one of those in a while, but when many companies were just starting to develop SSDs they occurred fairly frequently, though usually the manufacturer would figure out the problem and patch the firmware for new drives after enough failures in the field.