I have watched reviews on both of these models, both are 4S, and still being new to quads, what are the reasons to pick one versus the other?

I currently have a geprc 3 inch cinerun and enjoying that and want to try something larger.

They are both made for cruising. The 4" allows you to be under the 250g limit some people stay under.

The new Croc5 carries a full sized Air Unit with onboard video recording, so you can record better video image than the goggles.

The 5" also has larger motors to spin the bigger props.

Not a lot of difference between them, just one is a little bigger for people that don't worry about 250g. The 5"s larger size will probably make it better at carrying LiIon batteries for long flight times. They both get the new GepRC F7 AIO flight controller, both are made for similar pilots. The made difference I see is the weight. If you need to be under 250g you need the 4". If you don't care about 250g, then they now offer the 5" for people that want to record 1080p video through the DJI cam + Air Unit without having to carry a GoPro camera.

I like GepRC; I think they make really good frames, and use good components. Either one is a good quad, one is just a little larger and more powerful than the other, so it can fit a full sized air unit, and be a bit more stable in the air with larger props.

Thank you for sharing your input, that is helpful towards making a decision.

It all depends on what you want to do. Slow cruise with GoPro?. Some acro in backyard?. Fly far and mountain surf?

3+ years ago, bigger = better.
small quads, especially whoops were anemic weak.

Nowadays, 4" can do pretty much everything. Including carrying GoPro.
And even 3" flies very well as long as its not too heavy.

If you want DJI FPV, maybe Cinelog 30 or Smart35.