Just curious since you mentioned the lingering smoke odor as a major reason you didn't like the rig and then added the DSP didn't work as the secondary reason you were returning the rig, did you ever sit down and really work the rig with a thorough understanding of the manual? I owned a field in the early 2000's and it was quite possibly the best rig on receive I had ever used. The smoke odor could be dealt with and I don't know if you really had the DSP adjusted properly. It was close to first generation and wasn't like the current offerings we have now. The noise reduction of the DSP is only to help notch our or eliminate an annoying sound or other irritating noise while allowing the AGC to work around that "notched out" noise and bring the unaffected areas up to usable levels.
I never found myself in a position using my MK V Field of hearing a station I couldn't work. Sometimes it required more signal power via an amp, but generally I could work them barefoot if I could hear them. It sounds to me you weren't familiar with the DSP on board and it took some time to get used to it, and simply gave up on the rig. A little cleaner and some elbow grease would have eliminated either all or enough of the smoke so your nose wouldn't notice the odor and given some practice, you would have had one of the best receivers ever produced to use.
I have used the TS-590, the FT-920AF, the FTDX-5000 (overrated box looks impressive but doesn't do anything the FT-950 or FT-2000 PEP doesn't do) FTDX1200 and the FTDX3000. I have also used the IC-7410 (best receive audio I have heard from a rig of that price point) the overshoot issue was mainly over adjustment of the rig and it was only an issue if you used the alc line in connection with a linear amp to control peak output. If you run an external amp other than ICOM with it just use the PTT line and adjust your audio properly and no problems of major proportions exist. All radios will allow overshoot when operating, it is just some do it less than others, it is the bain of having adjustable mic drive and compressors/processors on the rigs and not being detailed enough to educate the user on how to set it.
I currently use many rigs, the IC-9100 is among them and has outstanding DSP, granted it is up to and with options, can be close to 4 grand out the door cover DC-light in on rig. It has 2 separate receivers, preamps that work, and a host of controls that even the most ego-centric knob and switch freak would need to satisfy their visual desires.
The biggest problem with most new operators is the practice or habit of not reading and understanding the manual. They just slap it up and plug in coax and expect their new appliance to work via telepathy. The expectations for rigs has now become 'oh it has DSP" and I should not hear anything but pure signal of perfect pitch CW tone or the mellow voice of the guy from pick your QTH transmitting. Please folks you didn't buy an automatic rig that will automatically set itself up to work as you envision it should. The older rigs receive close to what the new ones with DSP do, learn how to adjust the RF gain control and your mic settings. Yo might just find your clear audio gets responses and when listening a little white noise isn't the end of the world. Audio from a quiet background may sound cool but you are missing the other dozen stations you blanked out to get that loudest signal adjusted to your liking and the guy who is using that old FT-901DM has worked over a dozen by the time you finished adjusting your appliance so you don't hear that pesky low level signal of the DX station running 5 watts.
Having played with many if not most of what is available and has been available for the last 30 years, I don't care if I can get the last bit of hash out of the signal or I have to adjust my volume control (AF Gain knob) up or down, and/or the RF gain knob, working the station is the important thing and you won't remember the quiet QSOs but you will remember the times you had to really pay attention in noisy band conditions and was able to dig out that QRP op from the middle of nowhere.
Bottom line stop trying to be appliance operators and finding something to nit pick about a used rig, if it works then find out what YOU can do with it and to those who HAVE TO HAVE the latest FT-900000000000000 DX whizbang with the 20"display and stereo reverse DSP conditioning just remember, The conditions change and as long as you can hear them and work them that is and should be the goal. It isn't about spending $30,000.00 grand to brag about what you now have if you can't operate it and use the features, it is about how you took that $300.00 dusty rig of 30 years ago and worked the world.
I could go on, but I think you get the basic idea for now. Stop worrying about a little noise or interference if you can hear 'em you should be able to work 'em and that is the bottom line. I have worked many stations with 2 watts on a homebrew CW rig and a direct conversion receiver which I built, hooked up to a VEE Beam tossed out and over the edge of a hill running on a battery than many here. You don't need 1 gazillion watts all the time, you don't need perfect disembodied voices out of some processed background to work a station, you need to try it in all conditions as you can't always have the perfect path and you won't always hear all of what is out there if you cover or process it to death with goodies. Learn to live with a little hiss and you will find out you can learn to ignore the hiss and hear the little DX guy running a random wire on 5 watts in DX land just as well as you can hear the guy the next state over running a hundred on a beam, his signal strength my be lower or higher, but as long as you can make the contact who really cares about the conditions anyway...
73
KG6ABF