I have a 2006 sirrus that I use primarily for commuting (~10 miles round trip), and I really love it. I'm a little taller than you (5' 6") and mine is a 51, which makes me wonder if you should check the fit. At any rate, I am super-comfortable on this bike and before I bought a road bike earlier this year, I used to take it on all sorts of long (~50 mile) rides. It's held up really well too, no major issues with it.

I did, of course, replace the saddle, and I put spd/platform pedals on as well as bar ends. The bar ends were great because there just aren't many hand position options on those flat handlebars.

Good luck in making your decision!