What makes one Thermostat better than another?

Why are the more expensive thermostats better than the cheaper ones? I understand some have more options, like day night temp crops and so forth, but what inside makes one better than another? How do we know one is better internally than another? What makes one more reliable than the next one? And, lots of people sue cheaper ones as a back up. If they are more prone to failures, and are plugged in to the same line as the better ones just not the one that makes temp changes, wouldn't they cause a problem if they fail and shut the whole system off?
*Fila*

They're like anything else, you get what you pay for. I like the cheap Hydrofarms, they work reasonably well. I have a bunch of them going for around a year and a half without any problems. The temp keeping isn't the most accurate. I also have the expensive Herpstats. They work very nicely too, more precise temperature control along with a bunch of different features. To each his own, and whatever works for you.

Yeah you get what you pay for. I look for things that I want a thermostat to do and decide then what does it best. I have a herpstat a helix and several VE-300's. The herpstat has worked great on my chondro's cages for well over 6 years. I honsetly don't like my Helix but it does the job on the juvi-balls rack system. I love the VE-300's and the only reason I would change from them will be for the dual ve-300's that just came out. Search for what you want and then budget for it. This is one place that I would refuse to go with the cheapest thing you can find.

I can't speak from experience or technical expertise, but I've been shopping for a thermostat and basically what my research concluded is that the more expensive ones tend to be proportional thermostats, rather than basic on/off.

In other words they act like an adjustable dimmer to maintain the temperature rather than just turning the device on and off all day.

This can extend the life of your equipment, and provides a more uniform and constant temperature.

Cheaper thermostats tend to have less accurate probes. In most cases, this probably isn't the end of the world though, but greater accuracy is obviously preferable.

I can't speak from much experience (when it comes to snakes, at least), but I will say that in the past I've learned that when you cut corners on equipment, you will often end up replacing at least some of that equipment someday, and you'll have the pressure of doing it with a live animal on your hands. With that said, I personally think it's worth investing in a thermostat with a better reputation and higher satisfaction rates than a 'good enough' thermostat.

Just the conclusion I've drawn through research and experience with other pets. I'm still waiting on my first python.

What makes one car better then another? Features, reliabillity, functionallity, parts, etc. Why trust your collection to cheap crap thermostats? Johnsons, helix, herpstats, vivs, top stats

I meant what inside them makes them better. I know you get what you pay for in many things in life, but in this particular case, what inside them makes them better? Is it cheaper capacitors and diodes, brass vs aluminum vs silver, sealed housings as opposed to one that has cracks and so forth. I am in total agreement that the top of the line ones are far superior, I just wanted to know what guts they have that make them superior. I also understand the proportional vs on/off and the reasoning for one over the other, but are the guts of the hydrofarm lesser quality than the johnsons, and if so how so? I am trying to decide which top of the line one to get right now, cost is not much different on the good ones, but was just wondering what made them good.
*Fila*