Yes, it can be. At least until you hit the Orange County line about 10 miles north of Disneyland, then the freeway widens to 14 lanes and becomes very modern and free-flowing.
But up in LA County where they stopped investing in freeways back in the 1970's, things are pretty crummy and most freeways are poorly maintained and woefully inadequate for 21st century traffic loads. Especially during peak travel times from about 6AM to about 8PM.
Check out this local traffic website
http://www.sigalert.com/map.asp?region=Greater Los Angeles#lat=33.81796&lon=-118.09121&z=2
It will give you a good idea of what travel is like on the I-5 Santa Ana Freeway to and from LA County. But once you get into Orange County, things become much easier and much better maintained. As an example, view all the freeway cameras every mile in Orange County on that website, versus the freeway cameras once every 10 miles in LA County.
If you can make it to Orange County, you will be fine. But when you are in Los Angeles County, well, we will pray for you.