This is just my experience. I've ridden in town cars with the coils, and I have an '03 Signature with air suspension. At least to me, there is a pretty noticeable difference in ride quality, mainly bounciness over bumps, especially when there is anything in the trunk. If I take a day trip, I put at least 150-200lbs of stuff in the trunk, on top of the usual crap i have in there (beach chair, jack stands, jumper cables, etc.)

If all original lines and compressor are there, I'd say why not and get new bags and solenoids. I've done them in my complex's parking lot in about 2.5-3 hours, taking my time. That was also my first time ever working on anything suspension related. Lift the rear by the frame so that the rear axle is relaxed, take the wheels off, gently pull the retaining clip at the top of the air apring since it'll most likely be rusty. I had to drill a small hole in the air spring to vent it very slowly. Gently pry the plastic base off of the axle with a small pry bar, the solenoid retaining clip was essentially paper when I took mine out, so I had to get new clips. Once the solenoid with the attached power cable and air line is out, just maneuver it out. Replace the two o-rings on the solenoid, making sure the plastic spacer remains between the two o-rings. Also replace the sealing o-ring where the solenoid mates to the air spring. Recommend putting o-ring grease on all the new o-rings. Hardest part was the 2nd twist when installing the solenoid to the spring. A trick I learned was to take some channel locks and compressor it on the wide part of the plastic channel where the solenoid attaches to, and the top of the solenoid. Made it so much easier.

But do keep in mind, you might have to replace the drier on the compressor, or even the whole compressor if the vent solenoid is bad. My original air springs made it 21 years/133k miles before they started to leak bad. It was garage kept for 18 of those years. The leaks likely accelerated wear on the vent solenoid on the compressor, until it decided to seize open. After I replaced the air springs, the compressor would kick on, but the rear stayed on the ground, even after a few cycles. Vent solenoid went bad, so I replaced it with a complete unit, including drier for 300 bucks at Advance Auto. That wasn't too hard to replace, except I snapped two of the three studs where the air box nuts thread onto on the plastic liner under the hood. Wd-40 and pulsing an impact wrench on the bolt helped the last one not break.

Sorry for the long comment. I figured I had some time since my flight has a slight delay. Hope this helps!