However is there anything better in the form factor? Any suggestions that don't cost a fortune?
In that form factor at that price? AFAIK that's the best there is.
They're actually quite useful, given their physical limitations and price.
Horrible user interface? Yes. Poor bandwidth? Yes. (Only about 5Mhz in reality). Terrible bang per buck compared to (eg.) a DS1054Z? Yes.
They're obviously no substitute for a desktop oscilloscope, but ... they
do work
and they fit in your pocket and run on batteries. That's worth something.
There's a few gadgets that promise to turn your phone/tablet into an oscilloscope but I don't know anything about them. Maybe you could look there if the DS203 isn't suitable.