Largo's Assonant Binding https://everquest.allakhazam.com/db/spell.html?spell=1751 2: Decrease Attack Speed by 5% (L51) to 40% (L61) 3: Decrease Movement by 2% (L51) to 116% (L115) 4: Decrease AGI by 20 (L51) to 77 (L115) 6: Decrease AC by 0 (L51) to 34 (L115) Dirge of Salubra Rk. III https://everquest.allakhazam.com/db/spell.html?spell=35181 2: Decrease Movement by 50% What do lvl 115 bards use if they are the ones adding a snare to their melodies? A different song not mentioned?
The Dirge line of snares was added way back in OoW because snares with slow were being resisted by slow immune mobs. Also multi-slot snares (spells in general) are easier to resist because each spell slot adds a resist chance. So bards asked for and got a single purpose snare that would not be so easily and often resisted.
I think Largo's is better, but at high levels is often resisted. As a side story, in CotF beta there was an upgrade for the first time in many years to Largo's, Corpseflower's Assonant Binding. The detrimental effects were modded by instruments, and it was an extremely powerful debuff. Even though it never made it out of beta in this state, I would argue it would have been one of the most powerful debuffs in the game. To tune it down, the choice was made to instead have it cast Largo's Assonant Binding, which is almost universally resisted as it is a level 51 song.
I don't believe spell level has any bearing on resist chances. It's a function of the caster's casting level and resist modifiers and immunity.