Finally! At the third attempt I bought a usable circular saw. I was in the neighbouring town in Midland Tools where one can play with a large number of saws of many different kinds.
I had a good look at the CS5 (left handed) as well as the CS10 (right handed). I was keen to buy the left handed as that is what I am used to never having owned anything else. However:
1) The CS10 looked better made
2) The CS10 was cheaper
3) After going through many contortions I decided that when cutting two large pieces and using a straight edge the right-hander will give you a better reach.
Of the many other choices the one that caught my eye was a Porter Cable at Cdn$ 80. The Bosch was $115. I have never had a bad Bosch tool and this was a second shop where the staff expressed their doubts about this line of PC saws. The decision was not hard then.
I put it through its paces today. It is quieter than the other saws that I (briefly) owned. It had no problem dealing with 3/4" plywood and 2x4s.
I played with the blade adjustment to get it exactly perpendicular to the plate. Interestingly, if one gets it right using a square the cut is *not* perpendicular. After a series of cuts with adjustment after each it cuts just right. I wonder why that is?
Note to self: Get a better straight edge with integral clamps. Clamp placement to hold the workpiece and the straight edge so they do not get in the way of the saw is a science in itself