My first pair of riding shoes were some cheap Shimano's... fit good and worked, but were one of those super ventilated shoes. They were not ideal for cold riding at all. I figured it was time for an upgrade on shoes and started shopping online.
I had ordered some DMT's prior to these... ones with the ratched/cable system. They were beautiful shoes, but the most uncomfortable shoes I have ever tried (including motocycle racing boots). The fit was terrible for my foot. I began to lose heart and considered going to a LBS. But that meant spending 2-3x the money.
I broke down and ordered (2) pairs of Mavics (something I saw another reviewer do); one of the Zxellium Ultimate in 9 and one of the Zxellium in 9.5. I liked both of the shoes, and I figured I would let fate decide which I kept. It turns out that the Zxellium Ultimate in the 9 was perfect for me. My feet are pretty 'regular', maybe a little on the slim side. For reference, I wear a 9 in Redwing work boots, and a 9.5 in Sketcher shoes. My Shimano road shoes are also a 43, so the 9 sizing seems very true. Keep in mind the velcro portions are also adjustable (the little flap can be moved to 3 different settings, besides the velcro adjustability), so unless your feet are quite wide, these should be fine.
I have worn these shoes on a couple of 25-30 mile rides, and have been nothing but impressed from the beginning. They seem to need very little breaking in for comfort and are noticeably stiffer than my cheaper Shimano shoes. I have ridden in 35 F with very thin shoe covers with no problems at all.
If you are unsure on your sizing, I would recommend ordering a couple of sizes and returning the ones that don't fit... saves a lot of time and frustration.