Whether your website seems to load at lightning speed or snail speed is entirely up to you. It’s easy to blame the website software but the blame usually lies somewhere else.
It doesn’t matter which service you use to test your website speed. Each one has its own set of pros and cons. Use one or use more, whatever makes you happy.
Where you have your web server located and where it’s being tested from can have a huge impact on the results. My web server is in San Francisco, California and testing from another place in California can give me slower results than from Virginia. You should run a website speed test multiple times and from multiple places. Your best result will probably be correct.
Here are some of the services you can use, with the first one being my favorite:
My home page loads in under two seconds and starts to display in under two. Longer pages load in under four seconds but still start to display in under two. The only way to speed things up more than I already have is to remove some assets I can’t afford to remove.
If you have a dynamic website, use aggressive caching. Cached pages are as fast as static pages.
The more assets you load, the slower your website will be. You can’t avoid some assets, like style sheets, but you can lower their impact on your page speed. Less is sometimes more.