Yet another proud Steelheart owner here. There are some minuses to this device, but many pluses. Not sure I can call one day a proper review, but here are my first impressions.
Craftsmanship: Top notch. 10/10 across the board here. So rough weld seams, everything is uniform diameter and probably measures exactly to fit. I didn't actually measure everything to test, but based on what I know, it feels that way. The engineering work that has gone into this is impressive. The integrated lock is pure genius. The two connecting bars which fit into the base ring can pinch at first when putting the whole thing together, but properly stop any twisting of the tube.
Security: Hmmph. 2/10. It's an unpierced trapped ball device. No, I'm not getting a piercing. I think I figured out how the penis ring (called Penisring on the web site) is supposed to work to stop pullout. Since it is trapped behind the head of the penis, you would have to either pull out from the ring (very difficult, even with soap and water, if you can't manipulate the ring), or pull the ring out through the base ring (puts a lot of pressure on the scrotum at the base). Maybe this would be a problem with a smaller base ring (45 mm base, 35 mm tube, I think the ring is 32 mm outer diameter and 29 mm inner). With the degree of puppetry that my penis is capable of, I was able to pull out using both techniques. I was also able to re-insert, first into the penis ring, and then the whole thing into the tube.
Comfort: Wow, very nice. 10/10. I got the anatomical ring and the comfort lip edge on the tube. Both payed off very nicely. Of course a lot of this has to do with getting the sizing right, which I pretty much did, but I was able to sleep overnight in the device the first night without any problems at all. I didn't wake because of the device, and when I did wake for early morning repositioning and subsequent re-napping, there was just a mild bite which was able to be dismissed quite easily.
Hygiene: Could be better. 3/10. I liked the last device I had (MM Pet Trap) as I could easily adjust the head through the cage bars at the end and line everything up perfectly. This meant no problems urinating. Not so with the Steelheart. The fully enclosed end makes it very difficult to line everything up, which means you are basically urinating inside the tube, and then waiting for it to drain. The first time I did this, I ended up leaking out of the back of the device. Clean up requires lots of tissue. Clearly there is liquid still trapped in the device - I get this schwwwwtt sucking sound occasionally when re-adjusting the device. I think next time I would get something open at the end, like the Crossfire. Never would do anything with cage bars at the end, the way they press into the scrotum was a deal-breaker for me for long-term wear. Still, I got exactly what I wanted here.
Discretion: I wore it out all day at the mall. Did not even have to adjust once, nor did anything look out of place to me. This is with a 105mm length device. I think I may have gone a bit long on that, maybe I could cut it back to 100mm, but it is possible for me to reach the end of the tube when flaccid - just really difficult to push everything inside. The only visible part of the device that is out of place to me is the lock, but the profile on the integrated lock is pretty small. I'll give it an 8/10. Wouldn't be wearing this to the gym or under bike shorts, but every day use is it not obvious at all.
Some other random notes: the urethral insert was challenging to get into. I kinda didn't like it. It always felt like something could misalign at some point and then start very badly hurting. Mostly this is probably my own mental freak-out about this, as I am 100% new to urethral play. I tried urinating with the insert in, but I was dry at the time. Not sure when or if I will be putting that back in. Oh, it should be noted that was with the urethral insert AND then penis ring. One or the other make it difficult to get into the device, the combination is super hard. Maybe I will try with just the urethral insert, haven't tried just that yet. I think if I ever were to do this again, I would want either a longer insert or a shorter tube. The range I am at right now makes me nervous I could get soft and withdraw enough inside the tube to have the insert slip out, and then possibly not-reinsert properly, and this would be a big problem, which of course would occur, say, during an office meeting while you are the primary speaker.
The penis ring: doesn't help me with security, it makes a bit of noise inside the device when entering or re-adjusting. I think it has the potential to generate pressure points on me (29mm inside diameter here!). Did not leave it on long enough to get a sore, nor am I ready to try overnight. It is interesting as a toy, it does make erections less comfortable.
Oh, the other thing, there is this rather big elephant in the room that I've been neglecting to talk about. Yes, it is possible for me to orgasm in the device, even with the 29mm inner diameter penis ring, and the urethral insert. Each of these pieces makes it more difficult, but not in a good way, in a this-is-less-comfortable-and-I-will-probably-have-marks-from-this kind of way. This doesn't make me think that switching to a smaller diameter will help, it will just make the device more difficult and time consuming to put on. This was kind of expected, but, of course, a big let down. In the end, I think I've got a nice session toy, which can also be worn overnight, but there is no reason to pretend there is any sort of real security here or necessity to push into boundaries that cross my hygiene threshold. It does make it more difficult to climax and gives me a nice feeling while making love to my wife, but any type of device based OD is for me, completely useless.