Sizing of the Aldi Crane clothing can indeed be odd. In autumn 2006 I bought winter leggings and a winter jacket, both sized medium. The jacket was very big and loose fitting, but comfortable. The leggings were too tight and too short and only just usable.
In their spring 2007 offer of cycling clothing I didn't like the look of the jerseys on their website (manky colours and patterns) and decided to give those a miss, but once in the store they had very nice looking blue ones, so I got one plus a pair of shorts.
Expecting the same odd size on the shorts as on the winter leggings, I figured that due to the thinner and stretchier summer material a medium size would work for me this time. This turned out to be correct, the elastic on the waist band and the leg ends is a bit tight, but otherwise a nice skin tight fit. IMO wicking only works when a garment is tight against the skin. I also expected the Crane jerseys to be the same odd size as their jackets, so I bought a small instead of a medium size one, again hoping for a snug fit. The jersey fabric wasn't as flexible as I had hoped, it's a bit of a squeeze getting in and out of it, and once on it's still not skin tight like the shorts are, but it works well enough. Only real gripe is with the jersey zipper, it needs 2 hands to operate.
With Aldi prices I don't really mind the risk of buying a size that doesn't work, except for the jackets as they are a bit more expensive, but the jackets can be tried on in store. Just take a couple of sizes off the rack and step away from the usual "feeding frenzy at the zoo" scene that usually ensues when Aldi do cycling clothing, then you can try on a jacket and have a feel of the fabric quality without being in the middle of the maelstrom.