I bought the Progressive Industries PT30C earlier this year after looking at all the portable options. It offers a bit more protection against higher levels (Joules and Amps) and things like over/under voltage, open neutral, and reverse polarity protection, accidental 220v protection, automatic reset, etc. The greater cost is worth it to me.
The second one you linked to -Surge Guard -is similar.
DW, 3 Kids and our Goldens
2012 Shamrock 233S
2008 Toyota Sequoia 5.7L 4WD