As you've learned by now you need both AC and DC for etching.
edit: That is AC and DC both. I missed that at first glance. I just read the line "Two variable outputs (0-20VDC@ 2A), one fixed (5VDC @ 3A)" which didn't say anything about AC output. On the specs it does say AC/DC. Based on that, it would make a nice etcher, but as Stacy says, still needs pad, etc. $140 is sorta on the expensive side, and you can surely build for MUCH less.
[TABLE="class: specsalt"]
[TR]
[TD="class: specstop, bgcolor: #000080, colspan: 2, align: center"]Specifications[/TD]
[/TR]
[TR]
[TD="class: specs4, bgcolor: #CACCDB, align: center"]Input Voltage[/TD]
[TD="class: specs5, bgcolor: #EFEFEF"]120V AC[/TD]
[/TR]
[TR]
[TD="class: specs4, bgcolor: #CACCDB, align: center"]Output Voltage DC[/TD]
[TD="class: specs5, bgcolor: #EFEFEF"]0-30V DC, 5A max.[/TD]
[/TR]
[TR]
[TD="class: specs4, bgcolor: #CACCDB, align: center"]Output Voltage AC[/TD]
[TD="class: specs5, bgcolor: #EFEFEF"]0-40V AC, 5A max.[/TD]
[/TR]
[TR]
[TD="class: specs4, bgcolor: #CACCDB, align: center"]Output Voltage[/TD]
[TD="class: specs5, bgcolor: #EFEFEF"]0-110V AC, 2.5A max.[/TD]
[/TR]
[TR]
[TD="class: specs4, bgcolor: #CACCDB, align: center"]Dimensions[/TD]
[TD="class: specs5, bgcolor: #EFEFEF"]5 3/8 (H) x 7 3/4 (W) x 9 1/2 (D)[/TD]
[/TR]
[TR]
[TD="class: specs4, bgcolor: #CACCDB, align: center"]Weight[/TD]
[TD="class: specs5, bgcolor: #EFEFEF"]14 lbs. 14 oz.[/TD]
[/TR]
[/TABLE]