Hi Strapsils86,
I prefer ground mounted panels any day. The main plus is your not putting any extra holes in your roof and if you need to have a roof repaired or replaced you don't have a huge expense and solar down time, while you do work on the roof. Another pro is if you ever need to work on them, you can do so easily. As we age, our abilities tend to be hindered like going up on a roof. When it snows, you have easy access to wipe the snow off of them. The only cons I see about having ground mounted panels is that they can be stolen easier because they are on the ground but I don't think that is really an issue. Ground mounted panels typically cost more to mount as you will need more hardware but in the long run, that increased cost cancels out when you have to do a roof repair and you don't have that added cost to R&R your panels to repair or replace your roof. Remember, labor and materials will only go up, so those repair costs today will be double in 10 years or so. Ground mounted panels can be any size as you are not limited by roof space and layout! You typically can get a better deal on panels if you are not locked into specific sizes, brands etc. and don't have spend a lot of $$ on higher efficiency panels because space is not as much as a limiting factor. Ground mounted have better air flow so you will get more efficiency out of them as the cooler the panel is, the more power it will generate up to the maximum rating of the panel. Easy to scale if you want to add more panels later. If you mount them on the ground, you may want to pour a cement pad and anchor into the concrete your mounting structure. This keeps weeds and lawn maintenance out of your panels and looks a lot nicer. You can even mount your panels so you can manually tilt them in the winter to get a better angle of the sun for more power generation.
Ground mounted panels can have better protection from hail storms depending how you build your array.
You can also mount inverters near or under the panels and transmit the power as 120VAC/240VAC over smaller wires to your home. Don't forget to put all your wires in large conduit (Straight Run). Easier to replace, upgrade etc. and less likely to get damaged by shovel, roots or whatever else.
I designed a solar system for a friend many years ago that was ground mounted on concrete slabs with plastic covers for when storms approach. My friend has had to repair the roof 5 times and replace the roof 4 times in the last 32 years due to storms so had he mounted them on the roof, imagine the increased expense?
Well, that's my take on the subject.
