Great value on exceptional MIDI, just plan your purchase
This six pack is a great value compared to buying 6 individual Toontrack Drum MIDIs, it's what you'd pay for just 4 individual MIDI packs on Sweetwater or just 3 direct from the manufacturer's website.
If you're used to buying the individual MIDI packs or EZXs from Sweetwater and getting an instant download activation code, you'll have to be aware this is mail-only. Not a big deal, I just had to wait 3 days to get an actual software box, with a protective sleeve, with a printed card with the activation codes (apparently Toontrack requires it on this item and some of the other bundles).
When you're picking your MIDI packs from the (currently) 57 titles, spend some time on the Toontrack website reviewing the items you want, and look at the other 6 pack bundles and MIDI pack descriptions to avoid duplicating purchases. Each individual MIDI pack description on Toontrack will tell you if the MIDI is included in one of the full EZX EZDrummer expansion packs, or in an SDX if you're a Superior Drummer user. Toontrack makes sure it's clearly stated when that's the case.
For example if you're planning to purchase "Americana" or "Metal!" or "Indie Folk" EZXs in the future (total of 10 titles) to expand drum sounds, the EZX includes the same MIDI sold in the separate MIDI packs. Same goes for the "Indiependent", "Rock Warehouse", "Metal Foundry", "Progressive Foundry", and others (total of 9 MIDI packs) which are from the Superior Drummer SDX expansions by the same name.
Not a big deal if you're an EZDrummer user and don't need Superior Drummer's capabilities, you can still use the MIDI files that are derived from the SDXs. If you're just checking out the MIDIs and haven't fully committed to the EZDrummer/SuperiorDrummer experience yet, try picking a MIDI that's not already in an EZX/SDX so you don't duplicate a potential future purchase.
To maximize your value, you can use this"choose your own" 6 pack, or look at the other 7 "themed" bundles Toontrack offers through Sweetwater for the same cost. Of the 57 individual MIDI packs, 41 titles are in various combinations in the themed bundles ("Basic Rock" MIDI is the only one repeated in the bundles, appearing in both the Essential Drums and Rock Drums 6 packs).
The MIDIs themselves are really well done products. Natural feel in the performance, they work very well with either EZDrummer or SuperiorDrummer. Obviously you'll find some similar beats when you start collecting enough, but those subtle variations do make it easier to quickly build natural sounding drum tracks without individually tweaking the MIDI itself. I've found the more MIDI drum files I collect, the better results I'm having with EZDrummer's Song Creator, Tap2Find, and browse features.