i agree on bro mooncakes's comment...i like stk as it has more variety of kits, but the looseness will be there as it has been with its orig counterpart...BT makes it up for its tightness...its tight...sometimes to tight

go for STK if you want to have more zoid variety if your aiming to just build one type of zoid like the blade liger go with BT...i personaly like both

STK has:
- Gun sniper
<--OWNED- Gun sniper leena custom
- command wolf
<--OWNED- command wolf braad custom
<--OWNED- Liger Zero
<--POed- Liger Zero Schneider
<--OWNEDBT has:
- Shield liger/ optional guns to make Shield Liger MKII
- Blade liger/ Bang ver.
- Saber Tiger
heres a sample of my bootleg zoids

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my zoids coexisting with my gunpla

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WOW...without I realized, I already got most of the STK Zoids.