you need a software DVD player to play them
There's a freeware/shareware player for SVCD out there. Unfortunately since I've gotten both PowerDVD and WinDVD in bundles, I don't remember the name of it.
how do SVCD stand up quality wise? What is the resolution for instance?
Definitely better than VCD. If you go by the specs (more on that later), SVCD supports a maximum bitrate more than twice that of VCDs. I've tried both VCD and SVCD, and if the conversion is done properly, the rule of thumb is true - VCD is equivalent to a very good VHS tape with some pixellation in high motion/action scenes; SVCD is better than VHS and a touch below DVD. Because of the higher supported bitrate (and if you use it), you can reduce the likelihood of pixellation in SVCDs. The specs for SVCD are a resolution of 480x480 NTSC, 480x576 PAL, with a maximum video bitrate of 2.5Mbps and a maximum audio bitrate of 224kbps.
Here's where it gets interesting. Some players support noncompliant S/VCDs, which are generally labeled extended VCDs or XVCD/XSVCD. A good number of players that support SVCDs will play VCDs made at a higher/non-compliant bitrate. Off the top of my head, the Apex players, for example, will play S/VCDs with a bitrate up to 3.5Mbps. They'll also support non-standard resolutions, so when I was playing/testing I made an SVCDs with a 720x480 resolution at a 2.5Mbps bitrate. The joke is that the software players wouldn't play that particular XSVCD at all, but my Pioneer standalone played it like a champ. However, for compatibility I've stuck to the standard specs. The SVCD quality on the ripped DVDs is awfully good - better than VCD and much, much better than a dub to tape. Like I said above, I'm happy enough with it to question to value of DiVX (to me at least) at the moment.
If you're judging the quality of S/VCD, don't - I repeat, DON'T - look at commercial S/VCDs. I've seen several, and the quality was average to poor. In fact I'd ripped from DVD a few discs that I'd seen on commercial VCD. The rips I made from DVD were 10 times better than the commercial discs - sharper, with better color and sound.
I want to convert my VHS to CD's, and I want the highest quality I can find.
Quality-wise, if you want standards-compliant discs that'll work in a standalone player, you'd probably be better off with SVCD because of the higher supported bitrate. VCDs would probably be easier because I'd guess you'll capture at the native resolution for VCD (352x240). SVCD's higher bitrate really makes a difference in reducing pixellation. The only thing is that you'll have to resize/letterbox the video for SVCD because of the difference in resolution. The other option is a non-standard/XVCD captured at 352x240 with a higher bitrate. The Pioneers will support VCDs with a bitrate up to 2.5Mbps, so those discs would actually work in a decent number of players. That would be the best balance between ease of capture/conversion and quality.