Worst comm rig I've had? Hard to say. I've had 3 -- the Radio Shack DX-394, DX-160, and Yaesu FRG-7, along with a bunch of SW portables (DX-398, DX-390, etc.). The DX-160 was OK for a beginner back in the day, but its strength is a MW DX receiver. FRG-7 was tricky to tune on SSB on the higher end of the dial, making the 'Fine tuner' more usable, but its selectivity wasn't terrific for ham monitoring, although I did a lot of ham monitoring with it back in the day. It's pretty good for SWBC, and really great for MW DXing. Great sound. It will tune up to around 31 MHz, which is a plus if you've got the antenna and there's Low Band skip on 30-31 MHz.
I get good performance from my DX-394, especially on the ham bands, although I live in a low signals area, so I don't have to deal with overload the same way a lot of DXers would in other regions of the US (the 394 is famous for overload with longer antennas). Weakest part is some crosstalk here and there on MW, depending on conditions. I like the fact it tunes down to VLF. I use it a lot for ham band monitoring, especially CW. Being in a low signals HF environment, the DX-394 has worked out well for me.
The worst radio in general that I got was an off brand, $10 walkman style cassette/headset radio at a drug store in 2016 or 2017, that had DSP but no performance at all. It was definitely a locals-only type of radio, and even those locals didn't come in well. I was surprised, as most of the DSP pocket radios I've used are pretty good performers on both FM and AM.