There have been horrendous PC vs. MAC debates on this forum in the past; of which I confess I participated "enthusiastically". I must say in retrospect, I along with others on both sides of the issue, completely missed the point. We need to realize that computer hardware alone cannot decide the issue of what's best for video editing. The truth is the latest flavors of both PCs and MACs provide more than enough firepower to be superb performers in the non-linear video production field.
However, when it comes to personal computer-based video editing, it is the software more than the hardware that makes the difference. Also, you have to factor in the cost. On this forum, the prevalent expenditure for hardware/software editing tools is a sub-$1000.00 software investment and a sub-$2000.00 computer investment. It is really great that nowadays someone can invest that little and make a professional living in the video production field.
Within this pricing category, the PC platform undoubtedly offers more choices. This translates to the greatest flexibility, because more options mean more paths to success. On the MAC side, you have the formidable FCP Pro 4. On the PC side you have Adobe Premiere, Vegas, Pinnacle Edition, Ulead Media Pro, an on and on, and on. In fact, for the PC, you might be wise to use Premiere for some things, Vegas for others, and Ulead for even more etc. etc.
As for your comment about "less than smooth edited video", the majority of people on this forum, including myself, use PCs to edit video, and I've never experienced "less than smooth edited video", nor have I seen many complaints of that nature. Therefore, I'd conclude that this is something to do with your hardware/software systems in particular, and not a factor generally attributable to PCs.
No one can honestly deny that you have to have some technical knowledge to use PCs. Unlike Macs, the possible combinations of motherboards; RAM, CPUs, controller cards, etc. are endless. Not every hardware combination is ideal for video editing. In addition, your software might not perform as well with a particular brand of hardware. This is one price you may have to pay for the "open architecture" design of PCs.
If you're using a PC for video editing, my philosophy is to dedicate a machine for that purpose. Keep the installed software to a minimum" and don't use it for surfing the net or playing video games. PCs are cheap enough to own one for general purposes and one for a video editing station. Very general personal guidelines for an ideal PC editing system are: (a) use Intel Motherboards with Intel CPUs; (b) choose at least 512 Megs of the fastest RAM available; (c) Use separate physical ATA100 hard drives for software and video capture/editing (d) for Intel CPUs choose highest clock speed you can afford with hyperthreading, and 800Mhz FSB support being extremely desirable (note: AMD CPU-based systems are probably fine also, but I don't have any experience with them); (e) Use a Sound Blaster Audigy for 24-bit, 7.1 surround audio support, and built-in firewire ports (saves using a separate firewire card); (f) use an ATI All-In-Wonder video card because of its analog capture capability. A PC system like this will hold its own against any available MAC, including dual-processor versions, and can be found for maybe half the price (if you avoid famous Brands)