Just my opinion... this can be a sensitive issue so I hope no one gets offended here.
I'm a big Fender Jazz bass fan but haven't liked any of their recent Jazz or P-bass fretless models. I've tried a few Tony Franklins, American Standards, etc. I've even tried 4 or 5 of the Relic Jaco Custom Shop ones but even then there was only one that was good... but it was really good! I couldn't justify the almost 4k or would have bought it. I own an early 80s MIJ Jazz and poly coated the board, changed the pickups etc. and it's not bad but still not the greatest after investing a lot of money and effort. I rarely use it.
In contrast, check this out:
http://www.google.ca/m/url?client=sa...TjRX5wGYQJatMg
I customized a Peavey Cirrus which got me by but was never really happy until I got a used Pedulla Buzz 4-string for 1200 total and this bass is by far the best fretless I've ever played even though 20 years old and in need of a fretboard refinish.
Fretless basses are very difficult to get just right so you can get a wide range of tone. A part of playong fretless is constantly tweaking your setup. My standard is that I want to be able to play it all night and no one no even know it's a fretless to making it sound like a trumpet or trombone with tons of mwah and bloom. Make it howl! It's all in the fingers but it takes a really good, stable neck to hold this perfect set up. I am a firm believer in carbon fibre or aluminum stiffeners in a fretless neck.
I don't know where you are at with a fretless or what style you are into. MJaco? Hey You by Pink Floyd? Bach?
My own personal favorite fretless basses, after searching many years, is the Pedulla Buzz 4 string and the Rob Allen MB-2 to get a simulated double bass sound on the electric.
Both these basses in near mint condition can easily be picked up for around 1200 to 1500 used and even though you can get a big new discount, you can't beat used prices. A new Pedulla would be about 3500 to 4000 AUD for example.
If you are just starting out then maybe a Fender Jazz with a carefully selected straight grain stiff neck. Play it for a while to break it in and then find a really good luthier experienced in electric fretless to get the board tweaked and coated if you want more mwah. This is probably the least expensive option.
I have actually also tried a few Roscoe fretless bases with the diamondwood fretboards and was consistently impressed but they are again expensive and hard to find used.
Of course you can get into really high end 3k plus basses like MTD but they really only shine for 6-string jazz music IMHO.
Try the Warwick. I have played a few awesome fretted ones but maybe only one or two in the 30 or so I've tried. Try everything! If you are just starting on fretless then possibly just rent for a while until you get your technique down a bit so you can better decide before laying out the big bucks.
I find some fretless basses incredibly easy to play in tune and some others almost impossible. This seems to be independent of the setup. I often forget my Pedulla Buzz is even a fretless and have tested this by importing bass lines into Melodyne Celemony and found them dead on in tune. On the other side, my Fender Jazz is almost impossible to play in tune even though it has very low action with nearly perfect intonation. I haven't figured out why this is and it could be just the shape of the neck or something. Something to consider when searching around.
Try every one you can get your hands on and be patient! Don't buy it before you try it (unless a Pedulla as 99% are great - I've never read a bad review yet). When you find that right fretless bass, you will know it.
