Barth1234,
There are several things to consider. GoPro records excellent video, can take decent photos too; however, it does have some limitations and is not suitable for every user. Some want more detail and will go with SLR, some want to go inexpensive and go with more affordable competitors to GoPro, some want high end point and shoot quality and go with something more like SonyRX100.
Considering your questions and request for feedback, I'm think you have already decided to go with GoPro.
If you take good care of the unit, it will last many dives. Inspect the housing every time before use, check the gasket for shape, debris or anything that looks out of the ordinary.
If you see something that looks funny, use a new housing and discard the questionable one.
I've enjoyed GoPro for its simplicity, ease of travel and durability. We have the hero2 with dive housing, and have several hundred dives. It still works.
We have the Hero3 plus... my favorite one. Have changed the dive housing maybe 3 times or so. Has never flooded and still works.
In the last 3 years, we've been housing it in a Hugyfot Pro Plus unit, which adds 6hrs of battery life, nice large display and it's built like a tank. This type of setup is not for everyone. Some users will say that GoPro is not worthy of such quality housing; which I completely disagree. GoPro is a fine little camera and it's worthy to have great housings like the ones made by Hugyfot.
We also have the 4black, which we house in Hugyfot Pro plus.
The most recent addition is the GoPro Hero5Black. It's the best they've got thus far. We house it in the Hugyfot Vision Hero 5. Talk about awesomeness.
Hugyfot - Vision Hero 5
In any case, if there was some advice to share with you here it would be:
Give it a try.
Practice recording video and taking photos before diving.
Buy a GoPro plastic dive housing to start.
Check housing before every dive and keep it clean.
Store open in a zip top bag when not in use.
Buy extra batteries.
Get good memory cards C-10 or better.
Keep maintenance kit handy (lint free towels, eyeglass whippies) and don't let that get used for anything else than for your GoPro.
Invest in a tray. This will help stabilize your underwater footage.
Get a red filter, if you dive in blue water. I think you mentioned going to the Red Sea. Backscatter makes great filters.
Invest in a video light. If you can, get 2.
Get a hard case to store everything, transport it and protect things. Pelican makes great cases.
Last but not least.... practice, practice, practice.
Hope this helps.
Ricardo