That particular Art unit is the discontinued Art Pro Channel....Not to be confused with any of the cheaper and flat sounding units nor the Model 215 which replaced it. This is actually one of the nicer recording strips for the money a person can buy. I owned one for a while and even though it isnt 600 volts to the plates its not the typical 'starved plate' design a lot of the 'toob' mic pres are in this price range. It also has two different compressors in it and is switchable between the two. Optical and an FET based design if I remember correctly. I sold mine to purchase another piece of gear that I wanted more, not because I was displeased with its performance. I wouldnt hesitate to get another one if one came along at a great price. Real nice remote recording front end for a singer.
As far as 'mic pres under $300' this one would be at the top of the list as its usually around 3bills used.
Again, this is the discontinued model.....NOT the replacement unit.
I would never put one of these units in the same class as Ber*&^%#ger or Phonics or any of the other cheap chinese built(or worse) crap you can buy. Its not a Neve, nor is it an API, but its really a good unit (model 259, right?) and your 4033 will sound great through it. Especially for acoustic guitar. For your voice, you may not like the 4033, its a crapshoot there (my voice sounds great on mine) but a 58 through that unit will sound excellent for almost anyone.