That question partly depends on the features you need.
Most people will go for the Victor HV-MD2 if they need MUSE->NTSC downconversion, & the Sony MSC-3000 or -4000 otherwise.
I have presented an overview of models, including features & an attempt to put them in chronological order. The later ones, in general, have somewhat better video performance, use less power, & don't have cooling fans so are quieter.