I have f-5 S3's and Walsh 2 S3's. I recommend both highly as very high sonic quality per $. The f-5 are simply out of this world...no comparison. No conventional design can compare. Maybe German Physic Walsh's, high end maggies or high end electrostatics that cost much more....
If you want flexibility in room placement and good powerful and clean bass extension down to ~ 25hz, according to Ohm (I haven't measure this but upon listening believe it) go with the Walsh 5 Series 3 drivers. Ohm may have refurbished models with this available to save money over new Walsh 5 S3s. The F-5's are not as tall as new Walsh 5 cabinets, which I think is an advantage for most rooms.
I owned original Walsh 2's for 25 years. The new Series 3 drivers offer better dynamics, outstanding midrange (vocals are incomparable), clear neutral sound, smoother more extended top end, deeper and more powerful bass, and way more precise soundstaging...
I also own Triangle and Dynaudio monitors currently and have owned Maggies and larger B&W's in the past.
The F-5s bring out the best in all recordings, old and new. I hear things I never heard before in music I've heard dozens of times on many other speakers over the years, as a result of the coherent sound staging and other associated sonic attributes. They make me want to listen to everything I've ever listened to again. The coherency of the overall sonic presenation is magical: like you are there. Never heard original Ohm F's, but from other's descriptions I'd say these are comparable + 30 years of design refinement better.
The series 3 are the bomb. NEver heard series 2 so I cannot compare to those. I've read a lot of reviews of high end Ohms on the web. I'd agree with most of the superlatives I've seen tossed about.