I'm looking to buy some string cleaner to help prolong the life of my strings since the ones I use are quite expensive.

I play acoustic guitar and I use gauge 11 strings from Thomastik-Infeld's Plectrum range.

I'm debating over buying Dr Stringfellow string cleaner or GHS Fast Fret.

I believe the Dr Stringfellow cleaner has been around for a long time and is a popular, reliable brand.
GHS Fast Fret on the other hand comes in a tin as opposed to a spray, which sounds easier to apply, however some reviews say that it's a bit greasy.

Any suggestions?
I use GHS and have for 10 yrs now. I used to use Finger-ease. Both are just mineral oil with different ways of putting it on
2002 PRS CE22
2013 G&L ASAT Deluxe
2009 Epiphone G-400 (SH-4)
Marshall JCM2000 DSL100
Krank 1980 Jr 20watt
Krank Rev 4x12 (eminence V12)
GFS Greenie/Digitech Bad Monkey
Morley Bad Horsie 2
MXR Smart Gate
I've actually never heard of that Dr. Stringfellow stuff before. I've been using Finger Ease for 10+years and have never wanted to switch, honestly. Fast fret I'm not too sure about.