Uh oh, the cross post no no.... it's frowned upon here...heck it's frowned upon all bbs's. But your new so we will let you off with a warning
The advantage of a HDD system is that it is ready to go and it's all in one. You know it will work well out of the box. The disadvantage is that it is unexpandable. What you have is what you have. It won't change with the times. The bitrate and resolution you have now will be what you have 10 years from now. If you decide to upgrade because of advances in tech, then your unit will not resell for very much because it will be viewed as "behind the times". Also, if your into synths, you will be missing out on loads of soft synths that are out there.
The disadvantage of going PC is that it can be a royal pain to get set up. You have to pick a good soundcard, good software, make sure your system is streamlined, keep up on the newest drivers. It helps to be proficient with computers. You need to be prepared for problems in the start, and be willing to work through them. The advantage of a computer based system is flexability (you can change with the times), power (you are only limited by your computer), loads of plug in's and synths (looking for new sounds...they are out there), expandability (I can run up to 60 to 70 tracks w/effects, but if I need more I could upgrade my computer), and there are a lot of developers who are creating new things for DAW's that make it very appealing to have a computer based system rather than a static desktop system. The future looks brighter for those who have the flexability to advance with the times. The weather stays the same for those locked into a HDD system that can't change with the times.
That said, you will find you are probably more limited by your ability to record, than the source you are recording on. There are good engeineers who on a HDD could blow away my recordings on my DAW.
Good luck in whatever rout you choose.