Steve Pearson writes:

There's much less performance difference at speed than than one
might think.

There are two recent examples to support the relative performance parity, El
Penon 2018 and 2019.

https://airtribune.com/el-penon-classic-race-2018/results

https://airtribune.com/el-penon-classic-race-2019/results

The El Penon Sport Class meet is big air racing. In 2018 it became a match race
with two world-class pilots, Daniel flying a U2 145 against Rudy on the proto S3
155. I replayed their glides on Airtribune and couldn't believe how fast they
were flying, sometimes over 80 kph between thermals.

Rudy would slowly climb through Daniel and then lose 100 to 200 feet on the 5k
glide at 50% above best glide speed. That exchange repeated several times with
Rudy keeping pace with Daniel until Daniel eventually prevailed.

In 2019 Daniel flew an S3 against a mixed field of S3s and U2s and won again.
This time Rudy was flying a U2 but he was a little disadvantaged by taking off
late while administering the meet.

The bottom line is that the better pilot will win independent of choosing an S3
or U2. What the S3 gives up in high speed glide, it makes up for in climb. I can
thermal an S3 155 at the stall speed of a U2 145.

Calvin Hadley writes:

I have flown both, but a long time since I have flown a u2 with
four years of flying a T2C between. Every time I fly the Sport 3 I am amazed at
the climb rate the Sport 3 has and amazed at the glide it has. In my opinion it
is a very high performance glider and I love the lightness, which older people
would love.

Luke Waters writes:

Luke Waters I can't think of a pilot who I'd recommend buy a U2
instead of a S3.

David Aldrich writes:

 I can - someone newish, up-and-coming and looking to
eventually fly a topless glider. The U2 is a much better "transition" glider in
that it flies more like a high aspect ratio glider then a S3 (which flies more
like a low aspect ratio glider.) Pilots who spend a season or two or three on a
U2 generally seem to have a much better time on the T2/T3.

Steven Pearson writes:

David Aldrich that’s right. The U2 is best suited as a transition
to or from a T2.

Daniel Velez Bravo writes:

U2 and U2C are for those who wants to out perform the other sport
class pilots in competition flying. S3's are for those pilots that don't care
about beating everybody else (but its happy if it happens from time to time) and
want to enjoy the all around performance of a nice sport class glider, landing
with a nice smile every time even when outperformed by a U2 sky dog.

I love the S3 and would recommend it for casual flying and for some XC
adventures with low stress in mind. But would go for a U2 if I'm into
competition flying, personal records or are looking for moving up to a topless
glider at some point.

On my winning El Peñon classic race  2018, I'm confident that the U2 gave
me the possibility to keep up with Rudy on his S3, playing it safe, pulling out
that extra performance at the end.

This year 2019 flying the S3 was more demanding. I knew that I couldn't afford
to be side by side with a U2 when getting to final glide, nor even with Zac with
his higher s3 loading and fast glide experience. Rudy was not only too worried
about organization but was also on a bigger 160 U2 that's not an advantage when
climbs are over 2.5m/s average and glides where fast.

Just one last thing, during the 2019 competition on the S3 I got stuck low
during a task and would have probably landed if I was on a U2 but the S3 gave me
the confidence (sense of control) to deal with broken lift drifting over small
landings and climb out. So when low, I prefer to be on a S3 and when high I
would love to be on the U2.