IIRC fellw UU brother Tootler has one or has had one or both units - maybe he will see this thread and chime in.
I used MANY Tascam 4 and 8 track tape (open reel and cassette) recorders since the 80's until Cakewalk on Windoz in the late 90's and then Garageband since about 2004, and often wanted to see if it was simpler to use just to get a song idea down without having to get the whole shebang going on the computer or iPad, which is about a 10-minute procedure before I can hit record, and a standalone recorder would simplify (maybe shorten) that.
The Tascam tape machines and portastudios I used were always rock solid, and from reviews it seems that these DP series multitrack units are as well.
I agree with the idea from Jelow about having effects built-in, for a few extra sheckels, as it means less cables, connectors, and outboard equipment, and these DP series units even have microphones built-in, so for a quick song sketch, I don't see how you can fail, especially if you want to bring it with you somewhere...
Sorry I cannot offer a specific recommendation about the units in question, but I am also kind of 'perpetually' looking for something to reduce the friction from a song idea in my head, and getting it 'captured' quickly before the Muse has forsaken me. :music: