Thats not necessarily better in a PCIe SSD. Its better to know which SSD exactly we are using, instead of judging the performance just from the interface. While I agree that PCIe gives you the bandwidth to operate at much faster speed than SATA, not all drives take advantage of it. The best example is, once again, the Intel 600p.
As you can see here, the 600p (PCIe) is actually slower in reading small files than 850 EVO (SATA), up to 42% slower in fact.
Worse, it does all that while consuming more than twice (!) as much power
As I stated before, PCIe is not a guarantee for fast performance. It is down to each individual SSD itself.
Take a look at my post above, while Pro series might be too expensive for the V, Id say that the PM961 (similar to 960 EVO) has 90% of the performance while being not-that-much more expensive than the 600p, and it is more power efficient at the same time. The Plextor M8Pe is also one of those fast and power efficient PCIe SSD. Worst case scenario, even the 850 EVO is still faster than the 600p