I drove my 850 very regularly for several years - was fantastic and I had no reservations driving it everyday. While an 850 does need a little more persuasion to keep up with traffic, if you are in moderate peak hour traffic you'll be able to keep up fine anyway. Unless you like to floor it at every green light you wouldn't need much more than a 998 anyway.
As superseven mentioned there are some basic DIY mods that you can do which are easily reversible (i.e. do not compromise the originality of the car) but really improve the drive. My Dad used to have a 62 850 that he drove 50km each day - the car was stock standard apart from the following mods:
- Under bonnet original type fresh air heater
- Temp Gauge, Voltmeter and Tacho
- Radio
- Lots of soundproofing and carpet
- Retrimmed seats with extra padding in the drivers seat
- Right hand fuel tank (doing 50kms a day meant frequent refuelling on one tank!)
- Clubby retractable seatbelts
- Killswitches and green-knob battery isolator (any round nose mini is very easy to break into and hot wire

)
A few other +s/-s we've found with our 850s:
- Dry suspension requires less maintenance than hydrolastic (although a bit firmer ride)
- Sliding windows not quite as good as windups (and slightly less waterproof, but you get used to them and you can still get reasonable ventilation).
- No synchro on first gear not good if you are in very heavy peak hour traffic at crawling speeds (although most round noses had 3 synchro boxes)
- A nice tidy 850 in original condition is a very good investment!
- Ridiculously good fuel economy.
- You can fit your bottle of flashlube, your club lock, street directory, steering wheel sunshade, 2L bottle of coke/water/darwin stubby, $25 in small change, jumper, car cover and tinned asparagus in the front door pockets. Plenty of room!
- Above average rust protection for cars of the era, both 850's had way less rust than many mid 70's clubmans we have seen.
Anyway hope this helps, I guess the main point I'm trying to make is that an 850 (even mechanically unmodified) can still cut it as a commuter!
BUT It is of utmost importance that you post pics and details ASAP once you buy one!!! Good luck!
