I owned or auditioned a number of DACs before settling on the Isabellina.
Benchmark DAC 1, Electrocompaniet ECD-1, AudioSector USB, iRoc USB, Bel Canto S300IU. Also the Citypulse, Zhaolu, and probably a couple of other entry level DACs that I forget now.
Like many other NOS DACs, the Isabellina is somewhat laid back. But unlike many other NOS DACs it has both great micro and macro dynamics. It's resolving, but not ultra-resolving, and what it gives up in a little detail it makes up for in PRaT. It's relaxed and smooth and an awful lot like the turntable I have.
I heard a VPI Scoutmaster with a Sumiko cartridge this weekend. I didn't spend very much time, but from what little I heard, there wasn't much to distinguish the two. The VPI had better high frequency extension and sound stage depth, and the Isabellina was more dense and had better soundstage width. But all of these could have just been differences in speakers, room acoustics and associated equipment. I'd have to bring the VPI home and have an extended audition to really have a reasonable and informed opinion.
I have a JVC QL-Y66F with Dynavector 10x5 cartridge. Some of the guys in the vinyl circle (ChairGuy in particular) quite like the QL-Y66F and consider it a giant killer, comparing favourably to $2K+ turntables. I don't have enough experience with turntables to really say one way or another. I've stuffed the turntable with 7lbs of modeling clay, sprayed sound dampening rubber paint on the bottom, have a nice turntable mat, add brass weights and and it sits on vibration absorbing feet on a spiked Ikea LACK table on top of another Ikea LACK table. So really, all the tweaks I could muster without breaking the bank.
When comparing the JVC QL-Y66F to the Isabellina, and mainly I find that the biggest differences are in the quality of mastering. A lossless rip from a well mastered CD is very comparable to the original analog recording on vinyl. For example, when I take, say, a Norah Jones CD and compare it to the 180 gram vinyl pressing of same album, there's very little to choose from between the two. On the other hand, when I compare Brubeck's Time Out on vinyl to the CD version, the vinyl is night and day better than the CD.
My comparisons haven't been overly extensive or rigorous, but that's what I've found so far. It would be interesting if I had a $3000 turntable to compare the two, but funds don't allow for that kind of investment right now. Your mileage may vary of course ...