Aluminum hulls are mainly best for rocky environments, places with a lot of stumps or underwater obstructions, and very shallow water where you may scrape bottom at times to get through an area.
They handle abuse to the hull without catastrophic damage much better.
It's traditionally a lot harder to punch a hole in an aluminum hull than a fiberglass one.
They come in welded or riveted.
Welded is much more expensive, but way more durable then riveted which can leak if abused/stressed too much.
Aluminum hulls are generally much lighter than fiberglass boats.
They also tend to be noisier in rough water, (rattles etc) and typically don't handle rough water very well being lighter.
They often have much less flat deck space, and often the deck is not level with the top of the side rails. But there are exceptions depending on the type/configuration of the aluminum boat your looking at.
Fiberglass hulls are meant for speed and are very delicate and heavy.
I would never beach a fiberglass hull, maybe if it had a full-length keel guard (which lowers speed/efficiency) but otherwise you should ALWAYS anchor offshore and wade/walk in the water to the beach/shore.
I would be very leery to run a fiberglass hull in waters that have lots of stumps/hard underwater obstructions, or rocks.
Fiberglass damage can be repaired in most all cases, but it's costly and time consuming.
Aluminum hulls with major damage/holes are often a total loss as it's near impossible to weld/repair a hole in aluminum hulls from what I have seen.
If you fish mainly lakes and soft bottom deeper water with very little/no rocks, and your VERY careful to avoid stumps, and if your fishing larger bodies of water that can get rough, fiberglass is the best choice.
Me I fish rocky rivers/creeks, stump/tree filled waters, very shallow waters, and open water lakes. Basically, I prefer to be able to go anywhere freshwater. I have and prefer aluminum for this reason.
I stay out of the middle of big rough bodies of water though.
If I was rich I would likely also have a big fast 20ft fiberglass bass boat for big lakes/water only.
On trolling motors:
I also second the fact that a good trolling motor with more than enough power, in 24v or 36v is worth more than all your other equipment to enjoying your fishing time.
Spotlock is also a MUST HAVE for any serious fishermen, foot pedals are a joke.
I find them extremely uncomfortable, difficult to use, and your stuck standing at the pedal at all times.
I just upgraded from an edge 45lb foot control to a 55lb Riptide with spotlock and wireless remote.
My first fishing outing yesterday with it was life changing!
Boat control became a non-concern thanks to spot lock and the remote and I was able to focus 99% on fishing.
With the remote I can move around the boat anywhere at any time front or back, and have full control of the boat still, and spotlock in current or wind is a godsend.
With the foot pedal setup I was 60% dealing with boat positioning and 40% fishing at best.
Very nerve wracking and annoying, not enjoyable at all.