EDIT: I bought a 2nd one. This is in my bedroom behind my desk and I get on it every hour for 20 minutes with CNN on the TV. While it is portable I got another one for the family room. That makes it very convenient to use in the evenings when I am in that room for several hours. At this price .. it is worth having two of them.
This is the best of all my in-home exercise equipments .. and I love my treadmill. THIS stepper, every morning I put it behind my desk chair and every hour I get on it for 5-8 minutes. CNN on the TV and I take a break from sitting. That's why this is the clear winner. I don't even dress for it. I have solid slippers and I just step away, taking a break from all the sitting. I'm 5'9" about 145 and this is the perfect stepper. I chose it for the high looking hand grip in the pictures and it didn't disappoint; this is a game changer. You can be 6' tall on this and it will be fine. You could probably be 6'2" also. I can lean over if I need to but I doubt somebody over 6' or 6"2" can do that. Oh well. I bought this to strengthen my quads and move my butt. It is perfect for this.
People here have written that you can't go 15-20 mins at max as it will heat up. That's probably true. 5-10 min an hour is my plan. Down the road I might make it 10-15 mins. Time will tell.
I looked at 75+ steppers on Amazon and this was the clear winner. Not just because the price is reasonable but it is one of the very few with the hand rail being so high + a very very large foot pad.
Highly recommend.

Based on reviews from several sites, I chose this stair stepper because I wanted the most low-cost, basic, simple, entry-level machine. After a few days, I'd say it fits the bill. While it doesn't have adjustable tension per se, the adjustment of the stair height acts in that capacity. It seems sturdy, although when you are NOT standing on it, be careful to not let it fall forward. The lateral motion is easy to get used to. Not sure if there is a scientific reason for it, but it feels reasonably natural. The counter does what you would expect: time, steps, calories.
I'm overall satisfied but there is a CAVEAT that you won't learn about until you purchase the machine. It's not in the description, and it's not in the reviews at other sites: per the instructions, it can only be used for 15 minutes at a time, with a 30 minute rest period between uses. This is so the hydraulics don't burn out. Admittedly, there's no way I could go for longer than 15 minutes right now, but it's a bit cheesy that this issues isn't prominently mentioned. There are two of us, and we had hoped to use the machine sequentially, but now person #2 has to wait 30 minutes before it can be used again. So, this lowers the functionality score to 4 stars.
On the surprisingly plus side is the assembly. Being made in China, this product was likely to come with the usual gibberish English that makes no sense. But no! The instructions are actually clear and easy to follow, with good labelling and all the parts necessary (also labelled). The company gets 5 stars for clarity.
I will update this review after the machine has been in use to comment on durability and long-term performance.

Originally, I was browsing for a treadmill, but I really wanted something that would develop stronger muscles for walking uphill or step climbing (a few months ago I walked the length of the Grand Canyon, rim to rim, and I want to stay in shape for the next trip). When I read the reviews for this piece of equipment, I was still slightly undecided about it, but I chose to take the risk.
I've only had it for three days. I am 5' 11", 205 lbs., and 69 years old.
I had no problems putting it together; the base comes already assembled. The only assembly needed is with the vertical upright. I was very careful with the assembly instructions, and it took about 30 minutes to set up. But I went very slow. The equipment is made in China (imagine that!), so the instructions lack proper English, but they're manageable. The front of the base has a knob that will adjust the tension. The stepper makes very little noise; it's hardly noticeable.
The base is approximately 18" by 18".
Also, there's nothing to plug in.
Before ordering, I thought that the handle would be too low for me, but it's the perfect height. I have mine set at optimum height (same as in the picture in the ad).
Initially, I only took about 50 steps, and I was already breathing hard, so I got some rest. I felt that my leg muscles were receiving the exercise that I was looking for. Three days later, I'm doing 200 steps and then stopping. The air cylinders get pretty warm. I check the stepper every time I get off of it, looking for damage or anything loose. So far, everything is fine.
I've also discovered an added bonus: I can place my hands on the bottom horizontal part of the handle (grip tighly) and slightly lean forward while stepping. As I take the steps, I slightly push up on my upper body with my arms, causing my biceps, triceps, and chest muscles to also get a workout, along with my legs. I just have to be careful not to lean forward too much, so I won't fall frontwards. So be very careful with this.
As mentioned above, I've only had this equipment for three days. But so far, I am pleasantly surprised. Turns out that it was exactly what I wanted. And the price is very reasonable.
UPDATE: I've had this stepper for almost 8 weeks. I have worked up to 3,000 steps a day. However, when I get near 700 steps, it begins to squeal. I've used different lubricating sprays, but the noise is still annoying. I finally found something that works: I place a small fan on the floor, directly in front of the red tension knob of the stepper. This cools down the bottom area, and that eliminates the noise.
I'm still satisfied with the purchase.