The best sounding one for me definitely is These Days since it is so pristine and you can really feel the songs and each instrument in there.
Keep The Faith, Slippery and NJ also are sonically good but as others mentioned, they sound dated to their respective era.

The worst probably are WAN/THINFS which are both sonically a mud pool. Fahrenheit suffers from probably the most dated produciton of all Bon Jovi albums and has some weird style to it that I just can't relate to (even though I like many songs of the album itself).