Kevin, do you remember those old-timey Christmas tree lights? The ones where if one bulb burned out, the entire string went out? That's what happens. However, with solar panels, many have 3 diodes so that if one cell gets shaded, only one string of cells goes out. This means you still have 2/3 of a panel still operating; the entire panel doesn't fail.
If you have one charge controller for each panel, then having several panels is waaaay better. If you have one charge controller for all the panels, then it doesn't matter that much as long as you hook them up in parallel not series. If you hook them up in series, you will get the old-timey Christmas tree light effect.
Adding smaller solar panels means more wiring, but that isn't a big deal. It may be a big deal if you have to drill a hole for each solar panel to connect to each charge controller.
If you don't want to spend the money on charge controllers, you can use diodes instead for much cheaper and have a very small loss in resistance. This may help if you want to go several smaller ones in series.
If you have a long run of wire, then a large panel or connecting several small ones in series may be more advantageous.
What is more important than size is if it fits on your roof. If you can put more solar using smaller panels, then that is a plus. If one large one fits better, then that's the one I would go with. About the most one large, 72 cell panel will put out is 360 watts; 60 cell 300 watts; 36 cell 180 watts. Two 36 cell panels will have a different shape than one 72 cell panel, but, all things being equal, both setups will have the same output.
On my roof, I have enough room for one 72 cell panel at a max of 360 watts. Or I can do two 60 cell panels for a max of 600 watts. Or I can do four 36 cell panels for a max of 720 watts. Or, finally, I can do 9 of those itsy-bitsy, high efficiency 100 watt, 36 cell panels that have a small foot print and get a max of 900 watts. This is all without the panels sticking out over the edge.
The 72 cell panels are large and heavy so they are a two person job. The 60 cell panels are a one person job. The 36 cell panels are easy-peasy.
Shipping for 36 cell panels is often free. 60 or 72 will ship freight (semi-truck) and is $$$.
Different charge controllers have different amp, volt, and total watt limits; this may dictate whether one larger or several smaller panels are better.
You notice how I have lots of examples? It depends on what your individual set up is. Context is King. Keep that in mind as one answer isn't the best for everyone.
