I just purchased a Specialized Crosstrail Comp Disc. Pretty excited. Havent even had the time or weather to ride it yet but I have done a lot of size tweaking and general tweaking. I am 5'9" and weigh 170 pounds. Puts me right on the line between the medium and large according to Specialized. I went with a medium but I am at "8" on the seat post height (see attached photo…) to get about the right stretch on the pedal down-swing. I guess my confusion is this; Would a large have been better? Is it better to go with a smaller bike and max it out seeing as I am right on the line between medium and large? I like the idea of being a little more mobil and the bike and having some reduced stand over height but I am an absolute rookie and really don't know if I made the appropriate decision… Any and all opinions will help as I am learning a ton from these forums.

My opinion, is that you should be more concerned that the reach is correct. Which one is more comfortable to ride? One should have stood out as feeling better.

^^^What he said. Sloping toptube frames will have alot of seatpost sticking out;that's just the nature of the beast. But it's your reach to the bars that's most important. Are you too stretched out or too cramped?

^^^^ what they both said! All else being right (i.e. reach to the bars), and allowing for photo distortion, your photos indicate the bike fits you very well: that seatpost extension is more or less what one would expect. If you are 5'9, and your leg extension is right, then you likely (like me) have longish legs/shortish torso for your height. At 5'8.5", and with a true 33" cycling inseam, I would have a 'look' on a Medium Crosstrail almost exactly like yours. For me, at least, a Large would be huge, and way too long in reach to the bars.

If you don't feel cramped or too stretched out, the size is very likely precisely right for you, and you can make a minor adjustment to that with stem length (don't make that adjustment by sliding your saddle forward/back).

Finally, and opinions do differ on this, I am of the "if borderline between two sizes go with the smaller". My reasons are as yours, plus the fact that one can, within reason, make a very slightly small frame fit 'bigger' (stem; seatpost), whereas it is quite difficult to make a slightly too large frame fit 'smaller'.

I'm 6.3 and XL was too small for me. I went with XXL Crosstrail and it feels like custom made lol
My guess is you should go with L-XL, but it also depends on few other factors, including legs and arms length and so on. Medium sounds way too small. My wife is 5.6 and her Crosstrail version - Ariel is perfect in XL.
Everyone is different and badger1 have also good points about that. Go with your feel, ride some and you should be able to tell if its the right fit for you.

Not so sure I would go with larger than what you have. The Medium Crosstrail is a 17.5" frame, my DS8.3 is also a 17.5" frame. Both the DS and Crosstrails have similar frame geometries. My height is just a smidgen over 5'9", at 155 lbs, a little lighter than you but basically the same height.
I had test ridden the 19" DS (same as the Crosstrail large) and found it to be too long.

Here is what my DS looks like, setup for my height:

No disrespect intended, but, are you sure on this? The XL is a 21.6" frame. That sounds way too big for someone who is 5'6".

I totally understand you. That's how it is with bike sizing... Its a perfect fit for my wife. We checked M - it was silly looking, L was almost perfect, but XL was just perfect. Yes, her seat is pretty low, but handlebar reach is perfect. As I said before, we all are different sizes and lenghts.
She did many k of happy miles on that bike.

Keep in mind, that reach on the Ariel is slightly shorter than the Crosstrail in the "same" size. Looking at specs they appear equal, but with the added angle of the women's frame, effective top tube is slightly shorter. That, and many women have longish bodies, compared to their size. Stand over is also decreased due to the same angle of the top tube....

Occasionally, women's frames are different than men's.

The Specialized website has the Ariel top tube length listed as "Top Tube Length, Horizontal". This is the same as "Effective top tube" and is independent of top tube angle. On this particular bike, the Horizontal top tube is over 24", the stand-over height is about 33.5" and the seat tube is over 21.5".

Maybe the bike fits lopek77's wife but I stand by my original statement that this bike seems way too big for some one who is 5'6" tall.

That is the crazy part of forum and all opinions and experiences people have...We are both right lol

Agreed.