An eCheck is an electronic funds transfers (EFT), but not all EFTs are eChecks. EFT is an overarching term for many types of electronic payment: eCheck, ACH transfer, and bank wire transfer among others. Differences exist between them, though.
An eCheck uses ACH to transfer funds instead of a card network, so the fees usually are smaller. Wire transfers don't happen in batches, but are instead transferred manually. For this reason, wire transfers usually have larger fees.