I've recently been lucky enough to purchase a brand new Mayones Jabba 4 Custom jazz bass from the brilliant and helpful UK based Bass Direct (an official Mayones stockist).  I'd had my eye on one of these for a while but the Mayones website says they dont do a 4 string version, and being an exclusive 4 string kinda guy I had written off the idea of getting one.  Everything I'd read and heard about these basses suggested they were first-class hand made instruments so when a rare new 4 string appeared at bass direct I made sure I got in quick!

As you can see from the pictures below, the bass is a natural wood finish with a spalted maple top which give a beautiful detailing in the wood.  The body and neck are a Fender Jazz bass shape with a slightly modernised headstock shape.  The pickups are a slightly unusual Jazz neck and Humbucker Bridge pickup configuration (both Seymour Duncan 'Basslines' pickups) hooked up to a homegrown Mayones onboard active pre-amp.  The controls on the bass are pretty versatile featuring knobs for volume, pickup-pan, passive control, and a bass and treble cut/boost control for the pre-amp, there is also an on/off switch for the active circuit allowing you to fall back to a solely passive sound if you want.

The neck is a nice satin finish which is good news for anyone who needs to move around the neck quickly, the profile is a little wider than my Fender Jazz FMT but this is unnoticeable after a couple of hours of playing, and its slight less deep than the FMT which actually feels more comfortable to my hands.  Its also a 24 fret neck which is useful for anyone who needs to get up into those higher ranges.  The bass came with light-weight 35 gauge strings which I quickly swapped for my normal more manly 45 gauge swingbass sets.  The action out of the box was also a little high so I dropped it very slightly and reset the intonation and from that point onwards the bass played like a dream.

In playing, the bass sting tension is great, its at least comparable to the FMT and if anything it feels a little tighter allowing you to get some real pace up with no problems.  I think the tight string tension coupled with the incredibly versatile onboard electronics provide and very clear and strong growling tone which punches through in the mids and sits well in the mix (I play predominantly in a 60's function band doing mainly weddings, events and corporate functions, largely finger style and very little to no slap or tap other than for my own entertainment).  

The pre-amp itself has plenty of sweep and coupled with my TC Electronic RH750 can be made to produce pretty much any commonly used bass tone.  I actually have the onboard pre-amp rolled off a little as its very powerful and tends to dominate the tone a little if pushed up to the max, of course some players (especially slap bassists) may well prefer that type of sound, either way you wont be lacking for signal level or range of tone out of the bass itself.

The bass is a little heavier than the FMT but its body size is a little larger (which I feel contributes positively to the tone) and the bass feels VERY solidly constructed so its easy to forgive the few extra pounds. The neck is attached to the body via a six bolt system and seems very stable, the bass itself doesn't seem to loose tuning very much, even with relatively new strings, so I can only assume the whole setup is very stable.  The bridge of the bass is a work of art, full adjustable and capable of allowing adjustments to string spacings.  I actually found the string spacings out of the box a little on the wide side, but a few seconds with a allen key and a tuner and everything was setup perfectly and I now have no issues at all with the playability of the instrument.

Finally, the bass comes in a reasonably nice hard-case although I couldn't help but feel this was the only let-down the of the whole package since the case itself seemed slightly warped and had bracing cushions inside rather than having the internal foam properly cut away and shaped to the contours of the bass to hold it in place.  The case is also the rectangular slab type rather than a nice contoured shape, but it is light weight, seems tough and will probably be good for a few years use, and once the bass is properly stowed (using the supplied cushions!) it doesn't feel like its going to move around or get damaged at all.

So in conclusion, this is an awesome bass for the money, its easily a better instrument than my similarly priced Fender Jazz FMT with a more versatile sound, better stability and construction and better setup and playability options.  If you've got the money and you want something thats more than 'just another jazz' then I wouldn't hesitate to recommend one to you!  Pictures below (borrowed from Bass Direct).