I have the Erisin RK3188 unit. It's very good and does 95% of everything I need without issue. My only gripe is of my own fault really, in that the ROM storage is 1GB for app installs by default. Rooting it is easy and installing a custom ROM is easy as well which increases ROM storage to 8 to 16GB respectively. Of course this requires a clean wipe... Which I don't want to do as I've already spent ages configuring everything and getting all apps installed.
But thankfully I have all the apps I'd need now anyway so don't need to install anything else.
Other than that, everything else works. I have a 128GB USB stick with my music on, the latest Waze beta, LastFM scrobbler, GoneMad music player, Viper4Android FX (hugely important if you want to unlock the sound quality) and so on.
A note for these kind of units. Out of the box they will only support sticks and cards formatted to FAT32, not NTFS or exFAT I found.
I have a few vids online if interested.