The EE tape type was clearly intended for low speed consumer recording. It was a type 2 tape, equivalent to type 2 cassettes. BASF used a true CrO2 particle, & Maxell & TDK used ferricobalt equivalent (FeCo).
Obviously, EE was never aimed towards the pro/semipro market. For 1 thing, all 3 brands of EE were only offered in 1.0 mil thickness, the choice for home recording. Pro & semipro users bought 1.5 mil thickness. This reduces print through & has less tendency to stretch/break, important at high winding speeds w/ 10.5 in reels.
Also, only the BASF brand of EE tape offered back coating. TDK & Maxell did not offer back coating on their EE tapes, but did on their ferric oxide conventional tapes. The ferric tapes offered back coating as well as the 1.5 mil thickness, clearly aiming for pro use.
All multitrack & high speed (7.5/15/30 ips, half track) mastering decks I've ever seen or heard of did not offer EE capability. All EE decks were low speed (3.75/7.5 ips), quarter track. Again, this tells us that EE was a consumer format.
Still, EE was a good idea. I agree w/ a previous poster that had it been brought out 10 yrs. sooner, it may have had a bigger impact. It did what it claimed. The FeCo or CrO2 tape could accept higher hf levels before saturating, i.e. better hf headroom. On playback, the eq time constants were lower (less treble boost) resulting in higher s/n ratio. Tests confirmed that EE at 3.75 ips could match ferric at 7.5 ips. NAB eq for 7.5 ips was 50 usec, & for 3.75 ips it was 90 usec. EE eq was 35/50 usec for 7.5/3.75 ips resp.
So home recording of LP records for preservation could be done at half the speed. This not only saves tape cost, but head wear is greatly reduced. At twice the speed, the drag force on the head is twice. Also, twice the length of tape passes over the heads at higher speed. So the head wear is 4 times greater at twice the speed. Also, playing times are extended.
The downside to half speed EE recording is that hf loss due to azimuth error is greater at 3.75 ips by 4 times (vs. 7.5 ips). Also, wow & flutter at 3.75 is greater, EE type not being able to correct for these issues. Still, EE provided some substantial benefits. If brought to the market in 1970 (instead of 1980), it would have likely caught on.
At high speeds, ferric oxide is the better choice. At low speeds, CrO2, FeCo, & metal have higher saturation levels, i.e. MRL/MOL. Ferric oxide actually has lower distortion than all others until MOL is reached. The ferric MOL is lower than the others at low speed.
But at high speed the MOL is very well above 0 dB, so that ferric gives lowest distortion levels. Also, hf losses at high speeds are slight w/ ferric, but great at low speeds. EE can do quite well at 7.5 ips, & a little better at 15 ips. But 15 ips is where premium mastering tapes like 3M 250/226, Ampex 456, etc. really shine. At 3.75, these mastering tapes are quite poor, as they are optimized for high speed.