[Boatanchors] Which of these isolation transformers and variacs would you choose?

[Phil]

Hi All,
This spring I'm getting ready to add a few more things to the test 
bench.  Among the items anticipated are a couple adjustable/meered Power 
supplies to replace the one I built (the 13.6 V 19Amp one is a keeper).

BUT I'm also planning on adding both a variac AND an isolation 
transformer, 'just in case'.  I don't want/need very high wattage units, 
figure 300W or so is enough as I don't do large boatanchor transmitters 
(can't lift them easily).

Also, I don't do eBay, so that source is out.

Here are a few items I'm looking at, which would you choose (or none of 
them)???

Variacs:
http://www.amazon.com/Variac-Variable-Transformer-300va-Output/dp/B006NGI8VS/ref=sr_1_1?ie=UTF8&qid=1456872541&sr=8-1&keywords=variac

http://www.amazon.com/Variac-Variable-Transformer-500va-Output/dp/B006NGI2RS/ref=sr_1_3?ie=UTF8&qid=1456872541&sr=8-3&keywords=variac

http://www.amazon.com/Variac-Autotransformer-Voltage-Regulator-Powerstat/dp/B00CP9JT10/ref=sr_1_4?ie=UTF8&qid=1456872541&sr=8-4&keywords=variac

Isolation transformers:

http://www.amazon.com/Precision-1604A-Single-Isolation-Transformer/dp/B000LDLF3M/ref=sr_1_1?ie=UTF8&qid=1456872834&sr=8-1&keywords=isolation+transformer

http://www.amazon.com/Tripp-Lite-Isolation-Transformer-Outlet/dp/B00006HPFH/ref=sr_1_3?ie=UTF8&qid=1456872834&sr=8-3&keywords=isolation+transformer

A better buy?
http://www.amazon.com/Tenma-Isolation-Transformer/dp/B00PL0689Q/ref=sr_1_5?ie=UTF8&qid=1456872834&sr=8-5&keywords=isolation+transformer

http://www.amazon.com/300-Watts-AC-Isolation-Transformer/dp/B006NG977W/ref=sr_1_14?ie=UTF8&qid=1456872834&sr=8-14&keywords=isolation+transformer 


-- 
73 From "The Beaconeer's Lair"
Phil, KO6BB
http://www.qsl.net/ko6bb/  (Web Page)

PRESENT RADIOS:
Grundigs: S-350 (~2006), G6 (2011) & S450DLX (2014).
HOMEBREW: 7 Tube+Rect 1v3 Regenerative RX for LF (built 2015)
Icom:    IC-735 Transceiver (~1990).
Icom:    R-75, Cascaded 250/125Hz CW-Filt, Panadapter. (~2009)
Icom:    IC-7200 Transceiver (~2015).
R-Shack: DX-380 digital portable (~1990).
SDRs:    Softrock Ensemble II LF (built from a kit 2015).
          CommRadio CR-1A (~2015)
Zenith:  Royal-7000 Transoceanic Portable (~1968).

ACCESSORIES: HOMEBREW LF-MF Pre-Amp, MFJ-993B HF Auto-Tuner.
              HOMEBREW 8 Hz Audio Filter.

ANTENNAS:  88 foot Long Ladder-line fed dipole, 35 feet AGL for MW/SW.
            Active Mini-Whip, 36 Feet AGL for LF/MW/SW.
            37 foot "Low Noise Vertical", 11 feet AGL for LF/MW/SW.

Merced, Central California, 37, 18, 37N   120, 30, 6W CM97rh