They both come with 25 games each, all of them have 8 bit graphics although some of them were made recently as a homebrew indy project. They also both have a clam shell design and fit in your pocket.
I found this Scottish guy that tried out all the games and gave a verdict , he goes by the YouTube alias 'Crazy Burger and gave a very comprehensive review of all the games : Pocket C64 , ZX Spectrum.
These new systems won't take the vercade cartridges but they have a large folding screen and have 25 games preloaded.