There are physical differences between them: elasticity and hardness. I hope I'm not wrong to say that ZLC is more elastic (faster) and stiffer than ALC. However, the PROs usually go for ALC, as it lends more dwell and has crisper feeling. All in all ALC blades, IMO, are more versatile, covering a wide range of styles, from close to mid to far from table. But YMMV. I've tried ZLC blades ( Mizutani, Timo Boll) and a Super ZLC ( Zhang Jike) and do not like the way the ball shoots off the bat so quickly.
Not my intention to pollute or override OP, I just guess that I should write my first impressions on FZD ALC here. This probably is premature, as I've only used it for 3 hours, but what a heck, I do not have the means of an objective review, neither a true one.
I'm coming from Viscaria with Joola Rhyzm P Max FH and Joola Dynaryz ACC 2.0 on BH.
My FZD ALC had 87.1 grams when acquired (it got fatter while stored in my closet, 87.4 grams, as I've had a 65-70% relative ambient humidity). I've glued a pair of Joola Dynaryz ACC 2.0 (47.50 ESN hardness), total mass 187 grams.
The comparison between the two rackets is really not relevant and misleading, as Viscaria had 84 grams when new and now 88 grams, mainly moisture. My firts impressions with Viscaria were bad, as I felt it numb, empty and powerless ( with my poor technique). Feed-back had some vibration, but not enough to give confidence. If it weren't FZD ALC, I would have probably bought a new Viscaria.
Well the new setup is direct, fast, precise and punchy. Feeling is very crispy, sharp and full of information. The racquet is vivid and solid without being stiff. It's like my Viscaria on steroids. General behavior is the same, but everything is tuned up. It has all the attributes that I like in (my!) Viscaria, without it's cons.
VISCARIA
SPEED: 8.00
CONTROL: 8.00
STIFFNESS: MED
HARDNESS: MED-
POWER: MED -
CONSISTENCY: 8.50
FH/BH discrepancy: BH better than FH.
FZD ALC
SPEED: 8.50-8.75
CONTROL: 8.50-8.75 ( this is mainly at high speed, not relevant info for low speeds)
STIFFNESS: MED TO MED+
HARDNESS: MED +
POWER: HIGH
CONSISTENCY: 10
FH/BH balance
Bottom line: firs impression is great! New blade seems to have higher quality/value.
Well, I'm not saying that FZD ALC is generally better or different than Viscaria, just that my specimens have this discrepancy, probably my Viscaria was "low born".
I also have a XIOM 36.5 ALX, same structure, 87 grams. This blade also has a FH/BH discrepancy, better FH compared to BH. Probably due to lower stiffness, the blade favored FH looping. This lead to issues with topspin block, always have to be active.
Question: do you seal your blades?