free float handguard is easy enough to remove install to get access to the barrel. Barrel blocks seem bit cheaper then reaction rods, so if I don't need the tool yet then I can get the barrel blocks for now. It will probably be a while till I need to change barrels, and that would probably require a bit more tooling than just a reaction rod
One feature of the reaction rod is you get 360 degree rotation of the firearm to make it easier to work on, as well as vertical, horizontal and every other orientation in between. Most clamshell and barrel block style clamps will have a problem being clamped in a vise in any orientation other than horizontal give or take depending on the vise. Mose vise designs are difficult to adjust for horizontal orientation without very wide jaws or very narrow work pieces -- the vise part below the jaws is in the way.
If everyone used enough grease when they installed their barrels/barrel nuts, I'd be less apt to recommend a reaction rod. The fact is, you never seem to have any grease when you're installing the barrel. "I'll get some for the next time I remove it," but that rarely happens. That means you may have to really torque a barrel nut to remove it, and a reaction rod is the safest method IMO.
Some handguards use proprietary barrel nuts and/or connectors and wrenches. So, I'd agree that normally taking the handguards off isn't too difficult. If you don't have/can't find the right tools, it's a bit problematic. Completely depends on the way the handguard is fastened to the rifle.
Even though you are looking for these tools to perform a specific, limited operation (install/remove muzzle device), the reality is that the reaction rod provides the added function of removing and installing the barrel/barrel nut.
So, you may find that you'll be needing a reaction rod one day. That means you'll wind up buying both the reaction rod and the barrel blocks if you decide on the blocks now.
Rather than buy a one-time-use tool, you can easily find someone on here willing to loan out tools. If, however, you want to swap muzzle devices periodically and take them to the range to evaluate, then you probably need to buy your own for convenience.
The reaction rods are not cheap at all. I bought mine direct from Geissele for $79.20 with free shipping. I may have pulled the trigger on it while it was on sale -- it's been known to happen! Now the one I have is listed for $99.99, but all 3 versions they sell are out of stock at Geissele.
https://geissele.com/tools/gunsmithing-tools/reaction-rods.htmlI've seen other brands selling for a little more or less with various features. This Wheeler model is on sale now for $20 off at $59.99. It includes a gas port indexing rod. That makes sure the barrel nut is in alignment with the gas tube opening, but I'm not sure how useful that would be. It's pretty simple to do that indexing with the actual gas tube while adjusting the nut.
https://www.midwayusa.com/product/1021330574Just food for thought.