I don't really consider either having superior UI... but AWS's endless list of services when you click for the dropdown is a bit too much to handle. Not to mention how you'll have to use their search bar to get to what you want.
One thing I do credit them on is SSHing into an instance is a lot easier than GCP's "gcloud" way (I say this since I recently found the "gcloud" sdk to take over 10g on my laptop) and even if you use SSH on GCP, they make it considerably harder than AWS (although somewhat more secure for beginners... to prevent from attackers to getting to port 22).
Yeah that does work (which I have managed to pull off)... but I feel like it's a bit more of a pain (very slightly) to change the metadata, open up the ports and whatnot to ssh. I think AWS just tells you to download a .pem file and ssh.
In conclusion, I guess both ways aren't bad. I just seem to prefer AWS here because for me it was a bit easier than GCP because I ran into several problems when sshing to GCP initially.
The entire experience is much better, can you log into a EC2 instance that has no public IP with a simple CLI command that has no IP address or ssh keys to supply?
I never have any luck figuring out how to do most things in GCP. The disjointed UIs, the documentation that is out of date, etc leave me just going back to AWS.
I had such a different experience when I was trying out the two platforms in parallel about fours years ago.
I came from a background where we'd created/ran all of these kinds of services in-house - simply because we started building our stuff before AWS/GCP existed in any meaningful way.
Anyway, after switching employers four years ago I had a greenfield project. I had zero investment in either platform. (I had joined a hardware company with a responsibility to build the software org. Side note: don't do that. I now understand why hardware-centric companies often can't do software - the CEO and other key people in sales/marketing simply don't understand the field at all. And that does matter. They won't even be able to understand if you're doing a good or bad job.)
My impressions were:
1) AWS had many more services than GCP
2) GCP services were generally designed better, more carefully thought out, etc. I felt that AWS APIs were designed without a very large amount of thought put into it, on an individual basis. I imagined Werner Vogels laying out edicts for a generalized service API design, and the individual teams all had to follow them, or else. And then the individual team built each service, without being able to change the general API design guidelines.
GCP services meanwhile seemed they like they were built by a smaller (and more talented) team with more team cohesion and communication. They traded a better design for a slower API/service output over time.
* GCP gave me the feeling it was designed with taste, through every layer. Comparing this to the desktop platform fight; think Apple. Quality over volume.
* AWS gave me the feeling it was designed without taste. Think Microsoft. Volume over quality.
I'm talking about the combination of service design criteria, APIs, documentation, etc.
Another way of thinking about it: GCP is clearly designed by hackers schooled in the ways of UNIX over a very long time. Simplicity and elegance is valued very highly in terms of designs. For AWS: Simplicity is clearly not a design goal.
I've tried to use several different gcp services. I am forced to use their UI for setting up google play services and the documentation never matches the UI. Their pubsub services, when I tried to use them had broken documentation. It just feels cobbled together everytime I dip back into it.
One thing I do credit them on is SSHing into an instance is a lot easier than GCP's "gcloud" way (I say this since I recently found the "gcloud" sdk to take over 10g on my laptop) and even if you use SSH on GCP, they make it considerably harder than AWS (although somewhat more secure for beginners... to prevent from attackers to getting to port 22).