I love the LA610. I've had various pres through here over the last few years...Great River, Millenia, Vintech, Demeter, RNP, Brick, API 312 and 512c, A couple of the Adesigns 500 series...
While there are other preamps that made WONDEFUL sounds in combinations with given mics...the LA610 stays...because it always yields a good sounding track--be it bass or EP DI, vocal w/ condenser or Sm7b, Egtr amp with anything from a 121 to 57 to 421 to Um70s...even responsible for some nicely colored acoustic tracks with the Sm81.
The key is learning it's somewhat non intuitive gain controls. When I first got it, it fuzzed up seemingly everything...I had an assistant engineer in town show me how he gain staged it--ever since, it has shined. At some point, I replaced the 12ax7s for NOS 12at7s...it still has ample gain and kinda "nicened" the midrange a bit. I've used it with HELLA high output LDCs and low output stuffs like the 121 and Sm7b...all of the above turn out just fine.
It's a nice preamp. It's colorful in a musical way...but, less so than it get reputation for around here, IMO.