I recall once google came on the scene I ditched altavista and never looked back. I was a teen but my recollection was that Google included the relevant paragraph of text from the page shown in in the search results whereas altavista showed one line that was often indecipherable gobbledygook - perhaps the page title matched a keyword - and it made it so much easier to scroll through ten results and identify the one that was the highest quality
Plus the no fast no clutter homepage for google compared to how many links can we fit in one screen for the portals
There was a brief window where AltaVista improved and I went back to it after being Google since 98. Probably only for a few months. I often preferred the query hints you could give it to get very specific output. No matter, they went out of business.
The turning point that brought me fulltime to Google from then on (until recently switching to Kagi) was when they started having almost live results. It's hard to remember or imagine but search indices were often days, weeks out of sync for critical things like news, etc and Google was really the first to fix that.
Plus the no fast no clutter homepage for google compared to how many links can we fit in one screen for the portals