There may be one thing that you may dislike about attempting to modify a route by using intermediate stops. You will not be able to see the whole trip in one piece like you are used to in Streets & Trips. You will only see one segment at a time. This personally never bothered me, because as mentioned earlier I don't care much about modifying my route. But I'm mentioning it here because I can see how big of an issue this may potentially be to other users. If you plan a route from A to B to C to D, and when you zoom out you will only see the segment from A to B, or from your GPS position to B. The rest of the route will just simply not be drawn on the map yet. When you reach B, iGuidance will ask you if you wish to continue to C at this time. When you click or tap "Yes", then the segment between your GPS position and C will be plotted. Coming from Streets & Trips, you may find this one feature a bit limiting. Some users will not mind at all, and for some it may be a show stopper. It all depends on how one uses GPS navigation.
On the other hand, the experience during the actual driving will most likely be a much much more positive than using Streets & Trips. There will not be the need to place a myriad of check-marks into GPS Task pane before you can start driving. You just start the program, type in the address, and you are ready to go. iGuidance was designed to be used in conjunction with a touch screen, but the makers of the program thought of the keyboard users, too. iGuidance has several useful keyboard shortcuts. A tap on UpArrow or DownArrow keys very intuitively changes zoom level. Hit 3-key to toggle 3D-view, press N-key to toggle North-up / Heading-up. Hit M-key to mute, etc, etc. More keyboard shortcuts can be added with
iGkeys.
You mention you like to look at the screen while driving, and based on traffic conditions you decide if to take an alternative route. Yes, that's easily done with iGuidance. I normally drive in 3D-view, but if I wish to see an alternative route, I just switch to 2D-view and perhaps change the map zoom level, too. That way I can visually guess where an alternative route may be.