What do you play? If GT5, it's kind of hard to recommend the G27. The DFGT has all the buttons you need under your thumbs and is a very good wheel, and while the G27 on the other hand has a more comfortable leather wheel, better pedals, quieter, smoother and better force feedback, the addition of an H-shifter and clutch to GT5 aren't really that great. First of all, the H-shifter slows you down, and secondly the clutch isn't implemented that well; any gas applied during a downshift (i.e. a rev matched one) will put you in neutral when you bring the clutch out. Then getting back in gear is confusing and you waste a load of time.
So basically I personally feel like the H-shifter and clutch are a waste of time in GT5 and if I only played that I probably would have gotten a DFGT and a set of better pedals. (Source:I own a G27 and have spent a fair amount of time on a DFGT.)