The Flex 3000 and 5000 can do things the Icom 7300 can not.
First off, the antenna tuners in the flex radios actually work.
The 5000 can do diversity with dual receivers, and the radio has loads of ins and outs, 3 antenna ports, RX ports, balanced audio input port, etc.
It can also do HIFI audio reception for those who like fidelity.
The 7300 cuts off the audio at 200 Hz.
The new software has pro audio tools, a 3, 10 or 20 band EQ on RX and TX and filters you can set to whatever you want, 20 to 20,000 Hz if you want, or 300 to 2200, or anything in between.
Both are still quite high up on the Sherwood chart.
Surely not the worlds best radio but one of the best buys in used SDR rigs.
I sold my 5000 for a 6400M which is nice, great performance, but the 5000 was better in some respects. PowerSDR is better in some respects.
The Icom 7300 has put a lot of downward pressure on used radio prices with its $1000.00 new price, but I still find the flex radios to have some advantages.
Flex software is still growing, the Icom is done.
The computer allows more flexibility and control, you just have to know how to manage windoze.
If you just want to plug a radio in and work it, rigs like the 7300 are fine.
If you want to control things, the computer based SDR's rule.
The new software has CW work fine for me.