Well I can’t speak directly to the DRS Pro but I do own and shoot/compete with a FX Panthera 700, DRS 700 SHP and my centerfire PRS rig has the MDT ACC Elite similar to the DRS Pro but here are a couple of my take aways.
I’m shooting PRS/NRL22 rimfire matches out to 300yds using altaros king 40gr .22 slugs and needed minimum 1 moa consistent repeatable accuracy for at least 20 shots and a solid stock or chassis that can be weighted for balance and won’t have issue with flex in competition. On as tight a budget as possible.
I started with the DRS Classis SHP and swapped it into a aftermarket stock I adapted for it. It performed very well for me, pushing the altaros king 40gr at 905fps but I couldn't achieve the balance/weight I was after with the stock I had even after routing it out and bedding it with lead infill.
I was able to pickup a used FX Panthera 700 .22 that already had a sabertactical rail and bag rider and added a bridge and weights to it and for competition and it immediately replaced my DRS classic but I’d consider an aftermarket heavy forend a must have replacement over the stock FX forend.
This could come down to sample size and reg cycles but for me the Panthera has also been slightly more consistent with STD of 1.8fps avg and ES of 8-10fps vs about 2.5-3fps STD and 12-15fps ES from the DRS and while the DRS avg about ~.9 MOA 5 shot groups the Panthera was about ~.7 moa on avg @100yds and beyond
Servicing, its easier to tune the Panthera which hopefully is a one time ordeal but def a bit of a hassle with the DRS and its pretty straight forward to remove the liner on the Panthera vs the DRS requiring a degas and opening the air system.
On the DRS pro I believe you have two action screws but on the DRS classic it only utilizes one so that's another win in my mind for the Panthera as a more rigid durable system less prone to shifts but that maynot apply to the Pro. I’ve found the Panthera to reliable on holding zero so far with small bumps to the barrel/shroud in competition vs my DRS I had several times that zero shifted after taking a barricade bump but again that system is a custom adaption of the DRS classic that only utilizes 1 action screw and a bedded action vs the pro’s 2 screws and a MDT chassis.
All that said the MDT chassis’s are great and if your not a tall individual the Panthera has a pretty long minimum LOP due to the rear mounted bottle.
Also in my experience FX made a slight error in considering the pic rail length in relation to the action position on the Panthera and you will likely struggle to mount the scope with proper eye relief without offset rings which are difficult to use since its a split rail with a mag protrusion and most offset mounts are a 1 piece vs the DRS having the full range of adjustment for scope position and the ability to utilize high end 1 piece scope mounts if desired.
If the price was the same used I might go with the DRS pro for the range of adjustability and ease of installing weights with the MDT system and ease of setting up your optic but if you can find a deal on a used Panthera (or with some deals for as low as $1500 new) with an aftermarket rail for cheaper they are a sweet system.
Panthera is easier to tune, can be weighted and is a solid consistent system. And one thing to note is the barrel reservoir on the panthera is regulated vs the DRS is your unregulated cylinder so there maybe some minute benefit as far as barrel harmonics and consistency with the Panthera as well as it just being a larger plenum to work with.
DRS pro is more streamlined with less things to get caught on etc. once its setup but a bit of a pain to initially tune. And I’d assume the DRS Pro will come better balance from the get go with a well backed system for adding additional weight etc.
I was able to get 25 shots per fill with 40gr slugs at 905 and 912 respectively from each which is all I needed.
The Panthera scope mount is a pain point but ease of tuning and added shroud balance it out.