When I was 15 in 1965 I took guitar lessons and was told the best way to play is with the thumb acting as a foundation on the back of the neck. It allowed me to play a great variety of chords without straining, especially barre chords. I actually cringe when I see someone use their thumb on the strings.
The leader of my group constantly says that the E chord is not a friendly chord on the uke, so I stayed away from it, but when I started playing with an acoustic group of people in a park on Sundays a couple of years ago, most where guitar players and they key of E was used often, which forced me to learn the uke E chord. It actually didn't take me long, thumb on the back of the neck as a foundation, index finger on the A string 2nd fret, ring finger on the G string 4th fret and slightly pressing on my pinky on the C string 4th fret and also on the E string 4th fret. I play tenor only.
This is Michael Kohan in Los Angeles, Beverly Grove near the Beverly Center
9 tenor cutaway ukes, 4 acoustic bass ukes, 12 solid body bass ukes, 14 mini electric bass guitars (Total: 39)