Yup
If you compare the specs side by side between a 4 and 8 track cassette,the numbers don't lie.You'll get slightly better hi frequency response and less crosstalk with a 4 track because as you indicated,there's more tape surface available for each track on a 4.BUT,you've only got 4 tracks to record on!!! There is one unit that's no longer in production that rivals and even surpasses most 4 track cassettes,it's called the Tascam 238.It's a rack mount unit that sold when new for like $1300.There are some posts on this site's archives about it if you're interested,you can do a search.Cheers!