I was a competitive swimmer in my former years.  Now just triathlons.  This is a nice tool to work your stroke and breathing.  Takes a little getting used to, but I have no problem with turns or taking in water.  It will help you keep a linear stroke if you don't swim straight.  I like how it separates my breathing from my stroke rate.  I add a 200 easy with the snorkel or a few 100's when I do my drill sets.  Almost feels like a concentrated hypoxic set after using it.  I like it!

my son likes it.

Excellent tool to increase swimming strokes. Yet, if you have never used a snorkel you should make sure you keep to the shallower end of the pool for a quick response stand-up on the pool floor. Once you have it down (i.e. head position) you will enjoy the fact that you can increase the number of laps you usually do during a routine. Excellent if you want to build strength, stamina, and speed into your swim drill.

I have been swimming with this snorkel for 3 months and I love it.  I would recommend the extra "cap" be purchased as well.  I have not had any issue with water entering the snorkel.  This snorkel has allowed me to continue swimming despite a cervical disc problem.  I won't lap swim without one ever again!

It  has a little leaking while swimming but it helps to keep your mouth watery after 1 hr so you don't stop for a break...

So far I've had a problem keeping water out.  Purchased clip from Finis for top to help keep water out but it didn't seal correctly.  Unless you are a very accomplished swimmer you should order the more upright version of this snorkel.  Concept is great if you have issues with breathing when you swim.