along84, I see your concerns.
1. Quality of Picture Output
2. Quality of Lens
3. Effectiveness of System (Image Stabiliser etc)
4. Availability of equipment
For Quality of Picture Output, I have not use either camera. I used an older E3 before, hell the colour is more neutral than your entry level Canon. E30 is similar (being newer) in a way, close to E3 but not identical in my observations. There is a Vietnam photographer whom I met said that Canon's 40D cannot take colour photos. He saw many wedding photos by Canon using the XXD range in black and white only. Not sure if 7D is affected now.
For Quality of Lens, believes there is no comparison between mid and lower end lens. Canon is easily out of the picture with 7D. Do not believe? Just try them out. For top grade lens, it depends on what you shoot. Canon does not have something comparable to Olympus' 7-14mm/F4. The 35-100mm/F2 from Olympus is one of the crazily sharp lens. Talk about the vignetting, anyone?
For Effectiveness of the systems, I believe both have their advantages. In Body IS for E System, Swiveling LCD, Dust Buster System ever so effective. Canon I do not know, will have good points of its system as well.
For availability, have you ever wonder why Canon is so easily available? Quality over Quantity theory is one. Canon started off earlier and their market share is bigger. This should not deter you to create stunning photos. Patience is something missing in many good photographers' mind nowadays. If one cannot even wait for a chef to prepare a proper meal, what one can do is to get McDonald 24/7 Home Delivery at your comfort.