i recently began commuting to work (about 6 miles a day) on my Peugeot Monaco road bike. It's worked fine but Yesterday on a long ride (16 miles or so) It started making a funny noise while I idle'd. I figured it had something to do with loose bearings. I took it to my LBS and the mechanice said he'd look it over. I stopped by today and he had changed the whole wheel (and i believe the cassette).
It cost $35 but i'm worried because it's an aluminum wheel. I'm a pretty heavy set guy and I mainly started cycling for health purposes (and to save on gas). I'm really afraid of not riding on steel wheel since i'm kind of heavy.
also, i'm not sure what quality wheel, hub, and rim i got for $35.
Aluminum strength isn't something that I would worry about in this case.
I am also a heavy rider (over 300) and I ride aluminum rims. I rode aluminum 26" wheels when I weighed 365. I completed a metric century on them with high pressure tires at over 300...
I actually trust cheaper wheels more than expensive wheels (in general) because many of the more expensive wheels have light weight as their selling point, not strength. If you have 36 spokes, you are probably good, 32 is OK.
Your LBS should be able to tell you why they selected the rim they did and why they think it is appropriate.