Zoom H4n Pro: Affordable 4-track recorder with built-in microphones and phantom power for external microphones.
TASCAM DR-40X: Versatile 4-track recorder with excellent audio quality and built-in mixing and editing functions.
Zoom R16: 8-track recorder with 8 XLR inputs and built-in compression and EQ.
Behringer U-PHORIA UMC1820: This is an 18-input / 20-output USB audio interface ideal for recording studio sessions by capturing any mix of mics, instruments, and even stereo line-level sources and provides up to 96 kHz resolution for professional, high-quality recording.
The main differences between audio interfaces is the amount of Inputs/Outputs available but most importantly the dynamic range that will greatly factor in determining how high you can set the interface with out adding much noise that you don't want with other instruments or audio coming through and mixing.