I bought a Helite Turtle in January when they were on sale. I didn't even know such a thing existed until conversing w/ a possible craigslist buy with a guy who'd had some fell-off-a-ladder health issues. Said if he didn't get his price, he'd buy a Turtle and keep the bike. "A what?" Anyhow, I wasn't sure which brand to purchase but they all at least seemed like a bunch of extra safety even though I already ride ATGATT. I got the Hi-viz version and in truth, I feel a little silly when I see my reflection in windows while riding or being around the cool kids I come across here in San Francisco. They have a black version if it matters.
BUT, I enjoy commuting by bike, and I enjoy the thought of staying in one piece. I have noticed that I'm more visible to those who a moment before wanted to occupy my space, and the CHP guys don't even give me a second glance as I roll by (and I might sometimes be on the wrong side of the fog line..) I also ride very conservatively and don't split lanes above ~25mph. I'm okay with that. I'll be 52 this year and ain't nobody gonna mistake me for a hooligan. I also don't have an ST or any touring experience, but I'm keeping my eyes open for a sweet deal on something I can spend the winter getting to know and saying bye bye to cracked and hardened rubber and crustiness. I'm mostly just a lurker, but this is one thread I can comment on.
Getting past the silliness, my review is that when you hold it, it feels heavy, but I don't notice any heft while riding. I wear an Alpinestars touring/adv sort of style jacket with all the armor and a size large Turtle. I'm probably about 6'1" and around 170lbs. I tried xl, but it was way too big. They also have long sizes, but seems like you'd need to be pretty tall. I already notice I sit on the bottom of the back as is. An extra lanyard to attach to another bike is kinda silly at $25, but is the spare cartridge? I dunno, but me as a kid coulda put a lot of BBs out into the world if my airgun had that sort of energy source. Helite says you can remove the back protector from your jacket, but I have not. I might want to go Turtle-less and don't want to be compromised in my back protection. I really should check into that, but I fail to understand how protection from your protection could be bad. I'm happy to also say I can't tell you if it actually works, but the demo videos seem pretty convincing. I keep thinking it's like those movies where they throw a dummy out a window, it hits the pavement, the camera stops, the actor takes the dummy's place, shooting resumes and the actor jumps up unhurt. But it's real.
I would suggest the second CO2 cartridge to have on hand. For the Turtle, you're allowed six inflates before they ask for it to be returned for inspection. I suppose I'd want an inspection if I actually used it, but until I could get that done, I'd certainly keep using it until there was an opportunity for inspection (unless it was obviously damaged.) And I'm pretty sure if it disappeared today, I'd be at the shop tomorrow to buy one even not on sale. I can't really speak to heat - my commute usually starts in the low to mid 50s, and seldom continues over 80*. I'll most likely wear it no matter the temperature. Truth is I'm used to it and feel somewhat vulnerable without it.
I don't ride a lot on the weekends, so I'm not sure how much I'd use it if when not commuting, but were I heading out for a tour, darn right. I'd sure be happy to see more of us with this vest. Spread the safety and normalize the dorkiness!
-Ryan