For field recordings from slices, we recommend the DP-311 differential amplifier with active headstage.  This amplifier works equally well with both metal microelectrodes and glass pipettes.  The DP-311 is also great for extracellular recording, however, it lacks some basic features found in intracellular electrometers (such as electrode test and cap comp).

When it comes to intracellular recordings, we suggest the IE-251A intracellular amplifier or the IE-210 which includes some additional features.