45Colt Freedom Arms...
Echoing what Big Jim mentioned, the M83 is heavier and more hand-filling than the M97. So from that aspect, the M83 may be more comfortable on that basis alone.....at the expense of weight.
Many folks in your situation who have landed on a 45 Colt, end up getting a M83 in 454 Casull and opt for the aux cylinder in 45 Colt, giving you a supremely versatile package from mild to wild. Hunting, target shooting, whatever. That is why it's their most popular gun by a long shot. Also, the other wildcard is that the probability of finding a well cared for USED one in this configuration is far greater than finding a M97 in 45 Colt.
I also echo the comment about the adjustable sights. Better for resale, better for varying loads, etc.
The option of a M97 brand new is also a good one, although I'd try to handle one first if you think that the smaller grip size might bother you.
Lastly, just an observation from my shooting experience with the M83 and limited with the M97. A full power 45 Colt in the lighter M97 IS snappy, especially with a shorter barrel. The same load in the heavier M83 is much more mild due to how overbuilt that frame is (originally designed for pressures generated by the 454Casull). I have 2 454 M83's and one 44 Mag M83 and the 44 mag is a complete pussycat in the Model 83, even with full power loads. They are very manageable and borderline SOFT compared to similar loads in a S&W Model 29, for example.
Once again, the downside is that the M83 feels like a boat anchor compared to the Model97 (excuse the crude reference for such a fine firearm). The M97 is the way to go if a more handy and carryable gun is a high priority. I like them both and will try to add a Model 97 to my collection in the near future, probably in a 41Mag or 22LR.
Both models are awesome guns that exude quality and precision. If you appreciate those sort of things, and what it ends up costing to get it, you will never regret the purchase.
IC
Here is my 44 mag M83 6 inch (sunglasses not included)
FG M83 454 Casull
PG M83 7.5 inch 454 & PG M83 44Mag 6inch