Sorry I can't help you on a Maxon FL9 review, but I would take the FL-301DX (TS808-era) over the FL9 4-knob any day of the week. It's not as intense as the FL9, but not as metallic either; much warmer and can ALMOST double as a chorus.
I know you said small box, but the 'best in show' that I've ever tried (and still own) is the Ibanez FL99 Classic Analog Flange. If I can work some stuff around, it'll go back on my board. I've currently got the MXR Micro on there right now, due to the size.
The MXR Micro is fabulous for the sound/size/cost ratio; sounds great clean and does the 'jet plane' when you have a distortion in front. I generally like to dial in a sound and leave it, and that's where the MXR is right now. I do think a 'width' knob would have been a better choice instead of 'regeneration', but it's ok.