Reliability? CPUs in general is the least likely component to fail in a PC unless you abusively overclock it. No statistics exist as to which one actually lasts longer.
A 3rd gen Intel i5 CPU is definitely more powerful than the A8 APUs when it comes to processing power. The A8 may be equal to the i5 or perform better in programs that can use 4 cores though. Desktop i5 CPUs have 4 cores, mobile versions only have 2 cores.
If you are talking about the integrated graphics (iGPU), then AMD's Radeon HD 76xx iGPU are more powerful than Intel's HD 4000. A relative comparison would be a desktop Radeon HD 5570 (A8) vs. a Radeon HD 5550 (i5).
Intel mobile CPUs generally uses a little less power than AMD's CPUs so all things being equal, the laptop with the Intel CPU should have slightly longer battery life.