Maybe you mean Matrox, Lunar One. Last I heard, Maxtor were still making hard drives.
Matrox, for all their silly pricing and lack-lustre performance, used to make video cards with superb output quality. So far as I know, they still do. I think you will be flat-out telling any difference in picture quality between the Matrox and a brand-new card running DVI.
Notice though that I don't have any LCD screens that run at 1600x, and it's possible that your Matrox will run out of steam at that point. But there is certainly no sign of image degredation at 1280 x 1024 on any of my motley collection of much-loved old Matrox cards: all 32MB G400s or G450s. Oh, and I used to have some still older ones which are, I think, now retired. But they worked beautifully on the screens I had back then.
Note also that you will be relying on your monitor to get the A-D conversion right too. If the monitor's A-D converter is so-so, then you will lose quality. Ditto the cable. But, knowing you, you won't be running some cheapo screen, it will be a good quality unit, and even at 1600 it will probably cope just fine.
Remember that the degree of difficulty for analogue video transmission is determined by the combination of resolution and frequency. For any given video card, cable, and monitor, there is a certain point beyond which quality starts to degrade. What I'm geting at here is that even if your Matrox card starts to struggle at 1600x on (say) a 22 inch CRT where it is running at 85Hz, it may well be perfectly OK at that same 1600x on an LCD where it is only being asked to run at 60Hz.
Bottom line: yep, no worries. People make far too much fuss about DVI anyway. And for the sort of stuff you do, performance will be a complete non-issue. The Matrox will be just fine.