are you dead set on or need a digital scope? a decent used analog scope can be had for 50 bucks....
I agree though, with the prior poster, of the ones listed, the SDS1102CML+ at 299 is really a cut above the others. if you can swing the extra dollars, that's definitely the best of the ones you listed. (the + model having a higher resolution display over the older non + model)
that's always the problem though, you keep creeping up with features and dollars, you have to draw the line someplace.
at 350 you can get a 4 channel 50 Mhz RIGOL DS1054Z which can be hacked to 100mhz and has 4 channels and now all the decoder options included. (not sure if that's just a temporary deal though)
then at 460 you can get the 100 Mhz siglent sds1104x-e 4 channel with all the decoders, that can be hacked to 200mhz and lets you add a AWG and MSO functionality later...
so easy to keep creeping up in cost, but each tier has significant performance and functionality increases and it's worth it.
I ended up talking myself into a siglent sds1104x-e, and am happy with it.