X-bow vs Bow - my take.
X-bow has excellent damage 'out of the box', and also a little better accuracy without proficiency.
Bow is faster, but have very poor accuracy and damage 'out of the box'.
But what it comes down to is scaling. X-bow doesn't scale much, other than accuracy and a little bit of damage from the proficiency bonus. There's no real way you can boost the damage of the X-bow beyond that.
The Bow, however, scales very well. It goes from being frankly quite bad at early levels, to become godlike in later levels. HOWEVER, this does require a very heavy investment in stats. For instance, if you want to wreck face with a masterwork Siege X-bow (because face it - you'll never get a decent Mettenheim Arbalest dropping for you...), you need 20STR. To maximize your efficiency with the Ruby Runed Bow, you need 30 strength AND 10 statpoints into Powerdraw. Even if you don't want to go for the Runed bow, you probably still want at least 9 Powerdraw to maximize your accuracy.
Now, when you've made that heavy investment, the Bow is on a completely other level than the X-bow. It's fast, accurate, kills most enemies in 1 hit. BUT that's probably 6-9 attributepoints into STR that you could have used on INT. And if you take into consideration that INT gives a stat point, and you spent 9-10 on Powerdraw, that's 15 to 19 stat points you lose out on by going that route (21-25 if you're going HA, which frankly is overpowered like nobody's business).
Now personally I play more out of a roleplaying standpoint. Before I start the game, I figure out the characters background, and what tactics that background would suggest I use. Currently I'm playing a soldier based on the Roman Legionary, who used sword, shield, pike and javelins. If I modelled myself on the Turkish or Mongolian steppe tribes, I would do a Horsearcher build. For a British archer during the 13th century, I would go for a footarcher, and so on. I find this is a much more interesting way of playing, as you don't obsess with min-maxing everything, but play into your characters strengths and weaknesses.