9mm, .45 Colt, .38 Special and maybe .380 ... Midsouth don't have any Titegroup ... They do have W231
... will I be giving up anything if I make the switch?
You will be giving up Titegroup that burns hot and violent for slight reduction in accuracy from W231, especially noticeable in 9mm due to small internal case volume that expresses even small change in reloading variables. For other calibers you listed, you likely won't notice the difference in accuracy. It is temperature sensitive (Slower when cold) so if you are loading for match shooting power factor, you will need to add more powder to produce the same velocities.
BTW, Titegroup is preferred by many match shooters as indicated by this USPSA equipment survey -
https://www.thehighroad.org/index.p...-and-discussions.778197/page-11#post-12415502
But some bullseye match shooters still prefer W231/HP-38.
And FYI, HP-38 is same exact powder as W231 so if you can't find W231 but find HP-38, you can use it as same.
Here's close up of W231/HP-38
Both Titegroup and W231/HP-38 are flattened ball powder and meters well with around .12 gr variance for me. Titegroup has surface crinkles that may induce slight "bridging" while W231/HP-38 flows more readily so that may be a consideration when loading smaller charges for 380Auto.
9mm 115 gr FMJ/RN with 4.8 gr of W231 loaded to 1.130"-1.135" is my 9mm reference load that is fairly comparable to Winchester White box and produces decent accuracy (BTW, Titegroup, Bullseye, WST, N320, Sport Pistol, BE-86 produce smaller groups in comparison) -
https://reloadingdata.speer.com/downloads/speer/reloading-pdfs/handgun/9mm_Luger__115_rev1.pdf
I am always changing bullets to find the most accurate combination
RMR in-house jacketed bullets have produced smaller groups than many other commercial/match grade bullets and when compared to Hornady HAP (XTP without expansion cuts), produced slightly smaller groups in my testing. RMR FP/FN "Match Winner" has greater accuracy potential than FMJ. BTW, ELEY uses RMR bullets for their centerfire match ammunition so you are buying "ELEY match grade" bullets with 5% THR discount.
FWIW, during my .45Colt comparison test using Cowboy Loads, Bullseye, W231/HP-38 produced smaller groups than Red Dot/Promo, Herco.
BTW, W231/HP-38 is my powder of choice for 45ACP followed closely by Bullseye/Red Dot/Promo.