I ran a de-powered rack for around 7 years and now a manual rack for the last 4 years or so, all in the same spec car that my wife tracks as well.
Some observations:
The manual rack is easier to turn in low speed corners and in the pits or any low speed drive. In a hard, tight corner, the manual rack is easier, but requires more "turning" than the de-powered rack (due to the ratios), especially with a small diameter steering wheel. The manual rack is much lighter (weight) and easier to remove and install. HOWEVER, the inner tie rod ends are a major problem with the manual rack. The originals are NLA. The current replacements, which are made by Hamburg Technik are pure JUNK. I believe that they are actually made for a VW rabbit. (outer tie rod ends seem OK) They DO NOT hold up in racing. After burning through a bunch of them, I found an NOS set of originals, so I am OK for a few years.
If you have shoulder issues or lower arm strength, use a fully powered rack and live with the contant rebuilds for the never ending leaks. If not, the manual is the best choice, but only if you find one with great condition inner tie rods. The de-powered is not a bad choice, just a little less preferable.
Hope that helps!
Chuck