The DSP will suck some life out of your vinyl; I would try it with and without. For me, I am willing to put up with some less than perfect resonances for the sparkling purity of a well reproduced analog signal. There is a certain emotional thrill and sense of involvement that I get listening to records that just doesn't happen with digital sources (despite the fact that they almost assuredly measure better)).
That said, I have ploughed through a number of phono preamps over the years. Some of the best were built in to the 60's and 70's era electronics. If the piece of equipment has a pre-out, they are fun to audition.
Almost any modern phono-pre is going to sound pretty good. You will get a lot more variety and "bang-for-your-buck" entertainment value messing around with different cartridges. Before I would haul off and invest a ton of money on a phono pre, I would at least try out some different MM cartridges (Grado, AT, Rega - the Exact would be a good fit).
Moving into MC territory, it is more important to match the phono pre to the cartridge. Your selection of a phono-pre will be more critical, especially if you are moving up the price chain.
For under $1000 MM cartridges, I would recommend the Schiit Mani, although just about any would do. At this price point, the subtle refinements of an expensive phono pre will be barely discernible.