Technically speaking they are statistically less reliable since there is a SSD and HDD and two points of failure are inherently higher than one.
That said they are proving to be VERY reliable. Both are quality parts. Personally I wouldn't worry about how they hold up when making a buying decision.
Like others have mentioned it would be in your best interest to go with the 2tb or 3tb versions due to larger SSD's. Although even the 1tb will be an upgrade from what you are currently using. Not only will you have 24gb of SSD speed you will also have a 7200RPM HDD which is a significant difference in speed vs 5400RPM HDD....relatively speaking of course.