Yes, a PC is a more preferable choice if someone is looking for a reliable replacement for their current computer. The Surface is certainly very attractive - it is stylish, trendy and is an excellent option for an individual who requires a great deal of mobility. Unfortunately, this is where the comparison ends and also where a PC would prove to be of more worth. Many programs and applications run far better on a PC, and if an individual plans to rely heavily on their computer to complete substantial work and important tasks, a Surface would often not be up to the demands that a PC can meet.
Let's face it, tablets are amazing! You can play loads of games and apps, watch tv and movies and do almost everything you can do on a computer. That being said, there are some instances where you just need a real computer. Many new games are not able to run on tablets due to a lack of ram and processing speed. If you play these types of games you are much better off getting a PC versus any tablet currently available.
The Surface is likely to be just a flash in the pan, whereas the PC has been around for a very long time and is likely to be around for much longer than the new technology of the Surface. By all means have both in the house, but there is still something to be said for the PC - and many PCs are still very cutting edge these days.
I think keeping your PC is better. A Surface really is not that great of a device. It is underpowered and overpriced compared to what you can get in a reasonably priced PC, especially if you take the time to just buy parts and build it yourself. Surface is not worth it.