I've got two SPD3303X-Es, both of which were very easily software modded to SPD3303Xs for the extra digit of resolution on both.
They're very versatile, well featured supplies. I had one and wanted to replace a Korad 5A single channel unit and wanted an option for high current.... but the SPD3303X-E supports paralleling the channels for up to 6A delivered, or putting the two main channels in series to get up to 60V at 3A. It's also relatively quiet, the fan not even coming on in low usage settings, and the boot time is quick (just a few seconds). My main complaints with the Siglent are that the third channel has no readout (just slider switch to select voltage), though it's well regulated the readout would be great for fault finding and if it was fully adjustable, it would be more usable in other situations, then a couple quirks of the UI. Namely:
The arrow buttons under the main encoder knob switch between entries (like voltage, current, mode, etc) and the "Fine" button changes between digits the knob adjusts.... and I think that's just backwards. Use the arrow keys for the digit switching and then use the single button to scroll through the handful of on screen entry options.
The newest firmware has moved to display both set current/voltage and actual current/voltage, but made the live readout smaller.... showing set values is nice, but not so nice as to make the main display that much smaller imo. Maybe less blank space around the set current/voltage would give you another few pixels to up the font on the live readings.
The power and current graphs are a nice feature, but they're barely fleshed out. Being able to adjust the scales (zoom in on the voltage set not including zero, for example) and being able to adjust how long is actually displayed on the X axis would make it a lot more valuable as a tool and less just a gimmick.
Otherwise, though, they're easy to use and I'm happy to have them on my bench.