oh dear .. another 5-string thingy .. i suggest you go find a post that i did regarding the pros and cons of 5-stringers ..
Personally for me .. i feel that, as other shave said, you don't need a 5-stringer for that kind of music you are playing. If you friend is just a beginner i suggest that he/she get a cheaper one first to start off, i mean, sometimes just for the sake of interest a person takes up the guitar, then 2 months later give up playing, you know what i mean? But unless he/she is seriously interested in doing what he/she does, then go ahead with the budget.
Yes, and it's true, slapping on a 5-string is tougher than a 4-stringer. I'm a pure extended range bassist .. but slapping for me had taken alot of effort to pull it thru smoothly and cleanly without getting other strings ringing. But the wonders of a clear low B string when you slap on it is amazing, opens up your tonal palatte quite a fair bit.
Alot of good players out there use 4-strings and they are seriously good on it .. just a few, Marcus Miller, Victor Wooten, Geddy Lee, Victor Bailey, Domnique Di Piazza etc ..
anyway, Ibanez would be a good brand to look out for .. you can try getting their RD series .. good stuff ..