Looking at each:
Allan Herschell - only ridden the one at quassy - which was pretty unmemorable, and looks typical of their coasters
Arrow - Certainly had some good and groundbreaking rides - revolution, steeplechase, phantoms revenge, eagle fortress, but also had some suck - python at busch gardens, steamnin demon at great escape
Giovanola - too few rides to judge, but anaconda looks pretty awesome!
Morgan - not many to judge by, but steel eel was decent enough, and the others looks pretty good too
Pinfari - Generallly awful, althouigh grizzly bear at lightwater is actually "ok"
Schwarzkopf -= truly groundbreaking, Alpina bahn, teststrecke and olympia looping are legendary traveling coasters, Jetline, Lisebergsbanan, and even canonball express at pleasurewood are decent rideable coasters
Togo - according to rcdb they're still in business!
SDC - Only ridden skyways, which was ok...
CCI - They vary from "Meh" to "decentish" , but I prefer Gci and GG
DINN - yet to ride one!
RCCA - Much maligned, but bandit is actually quite fun..
TLDR - It's Schwarzkopf, and their shampoo's are good too!