That is an easy question I love to answer. Personally I would avoid combo units like a nest of angry wasps under a tree
In my opinion, one of the best brands of VCRs to use for transfering your S-VHS or VHS tapes to DVD is JVC units, they have excellent picture quality, picture enhancements and handle old tapes quite well. Most of the time combo units are made up with poor components, particularly the VCR part, which often breaks down and has an average picture quality and tracking problems, particularly on old tapes. Avoid those. I have my old trust JVC HRS-7500 (now discontinued) and a JVC 5912 (for S-VHS playback) and a regular VHS/QuasiSVHS JVC and I use those to transfer old VHS tapes to my Toshiba DR4 and a Toshiba DR5 recorder and the DVDs turn out outstanding. I use a Toshiba DVD recorder because out of all the ones I tested, it was the one that preserved the most colour and brightness info with excellent accuracy, low noise and no excessive filtering - handles 3 and 4 hours recording quite well and outstanding tuner quality, nothing like the LITEON garbage or Panasonics.
You might be able to locate DR4s on eBay, the DR4 has a frame syncroniser/TBC, it locks on to even the worst tapes / signals. (But do not attempt to copy macrovision protected VHS tapes it restricts it) All the other units I tested from Liteon, JVC recorders, Panasonic, Pioneer, etc...all had problems of their own either IRE errors, too much loss of detail (excessive softening filters), artiacts, etc. And I don't work for Toshiba