First bass I ever played on was a 6 string Cirrus. I had a good time, all my friends play guitar so I bought a 4 string Ibanez. At the time I felt inadequate with only 4 stings so I picked up a used 5 string ESP. I could play the 5 alright, but the Ibanez sounded better to my ear. I didn't really care for either the LTD or the Ibanez. I sold them both. By this time I'd been to a lot of music shops and tried out a bunch of different basses. No longer hung up on the need for extra strings, I just wanted to learn to play. I picked out what I felt was the nicest sounding, best feeling and playing bass out of a couple different stores, an active Fender Special Deluxe P/J. I'm also enjoying a $200 Squier CV 60 P bass I bought about a month ago.
I was over my friends house last week with my two Fenders. I know the Cirrus series are highly regarded, but I'm no fan of his sixer. I mean, it's OK, it looks really nice. Feels OK. Maybe I'm still too new, but it's just too many strings IMO, I NEVER use the C string. I don't like the tone a whole lot either. Maybe it needs fresh strings, or new batteries. Whatever it is, all three of the 4 string basses I've had sound a whole lot better imho. My Fenders (one Squier) and the Ibanez have way more "THUMP". The pre amp on my Fender Special Deluxe seems to have a lot more impact on the tone than the Cirrus also.
I really like 4's, the way they feel. I think they sound great. I know there are great sounding and playing 5-6 string basses out there, but for a couple hundred you can get yourself a KILLER sounding 4 string. I've still got an itch to find a good deal on a fiver, but there sure is nothing wrong with 4 strings, and six....maybe for a soloist or somebody with more experience, skill than I've got, I have no desire to own one and I hate it when I'm over my friends house w/o my Fender and I'm stuck playing around on his 6er.
Blues, classic rock and hard rock are what I'm into and the 4 strings suits the genres perfectly imo.