I always use Vector Magic. If I had to name a favorite graphics app, I think that's the one. It's been years since I actually compared it to Illustrator's conversion, and I didn't know much about Illustrator back then. I think it's superior to Illustrator's results, in spite of its simplicity, but it's been a long time since I really looked at that. I liked it so much more than Illustrator for conversions, and I never used Illustrator for that again. I have processed hundreds of images with it. I just use the online version because I can't afford the full version. Long ago this was free online, and when they started charging, I subscribed off and on. Now I use it a lot, and open the .eps file in Illustrator for additional editing.
I've learned to prep the image in Photoshop before vectorizing it. It makes a huge difference in faithfully tracing a line drawing if the original is anything other than fairly nice and sharp. I paint in contrast and clean up lines, and use as few colors as possible, creating sometimes a hideous image with areas of intense color intended only to make the vectorizing process work better.
When you upload an image to edit, be sure to "Hand pick" the settings rather than using the automatic system, which is maybe the default. The "Low" quality setting is often best, not "High". Choose "Custom colors" and again use as few colors as possible. You can add colors later in Illustrator or Inkscape as long as the areas remain separate.
It took me a long time to realize that when the image is ready in Vector Magic, it's smart to always click "Edit Result" and work a little more in the (very simple) image editor they provide. Those improvements are much easier than doing (most kinds of) corrections in Illustrator. For many edits, I think this would apply even if you're a super-pro with Illustrator. It sounds tedious to learn key commands, but there are about - uh - seven single key clicks (z, x, c, etc) that make the final image editor really fast, but those are optional. I like them, and I swear they make it more fun. The small bummer is that when you save those edits, you can't go back and edit more, and you can't choose to change the color palette or quality setting. If you try to do that, it smacks it right back to the history state before your edits.
And if you use the pencil tool, it uses up your alleged 1,000 available edits super fast, because every pixel counts as an edit. I learned to plan ahead in the image prep stage in Photoshop, so that I can use the pencil tool sparingly. I wish they would give you at least 2,000 edits. So those are my tips, and they have movies and stuff on their site, explaining how everything works. Essentially, it's extremely simple to use, with no learning curve to get started, and if you're starting with a nice, clear picture, the automatic setting sometimes works well, I think. But you can get better results than the automatic setting, and with practice you can get amazing results.
I should mention that you can use it even if you don't use Illustrator or any sort of vector app to edit Vector Magic's output. Often the output is very nice, and doesn't necessarily need editing. The final output does not have to be a vector file, and can instead be a raster image that you can edit in Photoshop or any image editor. And also I should say that some clear, crisp images vectorize really well without any prep ahead of time in Photoshop (or other image editor) so you don't necessarily have to know anything at all about graphics apps.