If you can, you might want to wait for the new Siglent to come out and for people to review it. It looks like it may well be a good contender. It'll only have two channels, and that might prove limiting, or it might not be, depending on your needs. It'll be a 200MHz scope, however, and that might put its price beyond what you're willing to pay after considering the competition and your bandwidth requirements.
If you don't need any sort of decoding, then the Instek GDS-1054 actually looks quite good, particularly for your uses (I'm presuming that 50MHz is more than sufficient for your needs), and especially because it has 4 channels. If you don't need 4 channels, you can get the 100MHz 2 channel model for $30 more (I'm going by the tequipment.net prices).
Of course, the Keysight is going to be the most responsive in terms of its user interface (it's been described as behaving as if the controls are directly wired to the screen), but it's potentially the most limited for the price, particularly in the memory department (100K points for the 50 MHz educational version, compared with 10M points for the Instek). If your decoding needs are limited to i2c and UART (assuming you need or want any decoding at all), then the educational model might suit your needs just fine, though the decoding is an optional extra from the looks of it (and I've no idea how much it'll cost).
At this point, there are a number of good options for rather good prices if 50 MHz will suit your needs. Looks like it's a good time to be in the market for an entry-level scope.