DVDs play in some not in other standalones

I just went from an LG 4041b to the 4163b. What I find odd is that with the 4041b using -R disk all of my standalone players would play them…even an older Toshiba. Now though when I burn disks with -R my kids DVD/VCR combo will not play. The other 2 units I have do. That sort of chokes me. I am using -R and have tried burns at 4x thinking maybe the 8x burn was causing problems. I just burned a movie on a DVD +RW and it does not work either. These are cheaper Emerson dual units. Also once the disk goes in it will not eject until I unplug and replug the power cord and push eject. The manual for these units says it plays just about everything.
Can anyone help
thanks

what burning program do you use ?

Using Nero 6.6.0.8…funny today I used a memorex -R and it plays, have been using Maxell. Think brand makes a difference?

Yes. Brand make a difference. More than brand, is important mediacode. Not all maxell discs are good. Any “Made in Japan” disc is the best.

Verbatim discs are very good, but the best are Taiyo Yuden (costly and more difficult to find, but the very best at all).