It's not "great", just average.
Even if you are lucky enough to get all your favorite boosts, have them leveled really high (90+lvl) and use 10k fragments, strength increase give you just 215-225% attack instead of 190% (13-18% of actual increase if you have fire phoenix and lvl35l AWs) for troops which are not covered by expiring buildings, and like 5% for main attack force covered by 4-5 expiring buildings.
Health effects are even less useful, as UUU and DA cover all types of units - my typical 255% => 270-275% = +6-8% of actual units HP (for the same 90+lvl of effect and 10k fragments), and it won't apply for all units.
+ increasing chance for HP boost effect for some type of barracks reduce the chance of getting strength effect for same type of barracks, making it almost useless to go past 11 diplomas for health effects, as it also adding more useless effects to the potion.
But yes, fighting-oriented effects are much better than others, at least they worth leveling.