Just received my $50 loss-leader Libra SL2500 - don't go out of your way to buy it - the Libra SX1500 IOS is way slicker than their worm drive.
Still a good buy at $50 - long spool stroke and built to last.
I do have a niche for this reel - letting my Cetus SS500 take a break on XUL seatrout. (four UL rods, four reels)
The worm gear oscillation is very crisp, but it takes slight, though noticeably more effort to wind this reel, even with a 50mm handle pitch. And I'll qualify that gravity on the handle will move the mechanism, so it's not sealed in concrete or anything.
Not surprisingly, unlike Shimano, there is a slight sound when the worm drive switches direction (but that's even reported with top-line Daiwa).
It would likely be harder to tell the difference in the 4000 size with its long 70mm handle - I really hate the flat handle grasp, though the handle fold design is improved.
I'll probably cobble out an inexpensive lightweight longer handle upgrade on the SL (Basszone or Gomexus).
Capacity is greater with a deeper spool, but the SL2500 spool is 2mm smaller loaded diameter (40 v. 42). Probably the real reason they chose to call this reel a 2500 size is it's 50 g heavier than the SX1500.
The bail function is wonderful (including auto close - just say no), the drag is wonderful with fine adjustments, and the drag sounds wonderful.
Anti-reverse is also optional on this reel, and no added drag feel with the roller bearing clutch engaged, but it already begins with too much. They just don't have a slick worm drive like Shimano and Daiwa (but this is also $50 v. $200).
Like every Tica reel, feels built to last.
The Libra SX still wins for slicker function, lighter-weight mechanism giving remarkable line management with long stroke (and I like the handle grasp).
ps - balance of the SL2500 feels great on my 7'9" Takamiya rockfish UL
The slightly lighter SX1500 will go on the 7'6" XUL.
Note the weight of the SX1500 is not significantly more than the Stradic FL1000 - 20 g (the Stradic FL1000 is sold in Japan as the C2000SHG)
pss - if you're wondering why I'd go to this effort -
Arroyo dock fishing - changing up lures is everything, plus rods to loan.