In my own house I have a dish both at rear and at the front of house, rear one is high and the Sky engineer refused to work on it due to poor access even when they fitted it to start with, the lower on at front does suffer from snow with heavy winters as it builds up on the garage roof in front of it, but it's also easy to clear the snow, at home I gave up with freeview simply because of the continual re-tuning it seemed every other week we had to re-turn.
Mothers house we have both on same box, because the box is not freesat but free to air the program guide is not very good, but on the other hand I can set order of channels so next to ITV3 is ITV3 + 1 which seems to make sense, rather than hunt for the +1 version after some one has called. Although there is a ITV3 + 1 on freeview every time I come to use it I find the + 1 is not there, I have also less problems with isotropic propagation with satellite than with terrestrial.
Because the TV will auto change channels at the appointed time and the sat box just records the channel I use both, and set sat box to record and TV to auto change, but the quality from HD sat and terrestrial seems better than the TV with most programs, however the picture adjustment on the TV does not extend to that coming from the HDMI input so there are times due to TV design where freeview picture is better.
Up stairs we have two Sky boxes, the very old one like the TV down stairs can be set to auto change program, the Sky+HD box only option is to set to record, the picture is better but not due to using satellite it is all down to controls on TV and satellite box. I have freeview on one up stairs TV, we never watch it, simply because the old Sky box has a very good electronic program guide, and the freeview guide is rather hit and miss, also the order of channels is all messed up.
So the selection between satellite and terrestrial is mainly due to equipment used to receive them, even the continual swapping of channels is down to equipment used, some TV's seem to auto update, others need a complex procedure to retune.
As to aiming satellite dish tried with the cheap meter, yes can be done, but last time set up TV on the lawn and watched the bars on the TV, worked far better, OK for those who have expensive boxes which can be set to satellite required, but those cheap boxes are not much good, I have seen my son-in-law with his mates boxes tuning them in to turksat so then they can take them home and line dish to Turkish TV.
Personally now I am lazy, it's a lot of work setting up TV on the lawn, so I pay the few pounds now to get some one with box to set it up, today loads of programs my mother could watch on the SkyHD+ box, but the free to air box only programs were from 1950's that interested her, but those were only on the free to air satellite, there was nothing on the freeview. But she is 92 so 1950's movies suit her.
