Again, “better” has to be measured against budget and use case requirements. Different bulbs definitely have different features.
The first thing to look at with any device is the warranty length. That will tell you a lot about the engineering and quality. And it varies a lot. You’ll find some devices with a 90 day warranty, A one-year warranty, a five year warranty, all in the same device class. But then the ones with a longer warranty probably cost a lot more.
As far as specific features, again that varies by device class.
Pocket Sockets
Pocket sockets are typically available in either Wi-Fi, Zigbee, or Z wave.
They usually come in one of two types: lamp modules or appliance modules. Lamp modules are usually capable of dimming a dumb bulb. But you should not use them for anything with a motor, typically small appliances like a coffee maker or a pump or a fan or a motorized window covering.
A lot of manufacturers will distinguish these by not putting a grounding plug opening in the lamp module. That’s to prevent you from accidentally plugging in something with a motor, since almost all of those have a three prong plug. Plugging something with a motor into a dimmer control can burn out the motor and even cause a fire. So you do need to know what you’re going to want to plug-in before selecting the device.
Protocol
As far as whether you should choose zwave or zigbee or Wi-Fi, Z wave and zigbee devices use much less energy than Wi-Fi devices. Typically about 25%. So you save yourself some money by choosing those. Also some Wi-Fi devices tend to drop off the network every two or three weeks, which can be annoying.
Your Zigbee/Zwave network as a whole will be more efficient when you have more devices that can “repeat” which most pocket sockets can. So in general, it’s good to have at least one repeater per room of each protocol that you’re going to use.
Some people use only zwave, some people use only zigbee, a lot of people use both. Any of those is fine. But you do need to have a repeater about every 40 feet. In your case one in each room would be enough. So that can affect your device selection.
You haven’t said anything so far about a doorlock. If you want one that introduces some other issues.
Zwave plus is the newest generation of Z wave. Smaller devices, better battery life, better range. So most people would choose those over the older Zwave unless cost is a major factor. We are just starting to see a few devices come on the market in “zwave plus V2”, or the 700 series, which will have even better range in some set ups. But regular Z wave plus is good enough for most people.
Zwave S2 is the new security level. So you will start to see devices advertised with that. Not really critical from most residential pocketsocket applications, but it’s new, so you will see manufacturers calling it out.
If you want something that also works with HomeKit, it will probably need to be Wi-Fi. Wi-Fi is also best if you want real time energy monitoring. And these days the Wi-Fi devices are often less expensive because the market is bigger.
Wi-Fi devices can run locally with HomeKit, but the smartthings WiFi integrations are all cloud to cloud, so that’s another factor. Zigbee and zwave Pocketsockets may be eligible to run locally with smartthings, but only if they don’t use custom code and only with the official smartlighting feature.
one outlet or two?
As far as other plug features, you’ve noticed that some of them cover both outlets in the wall receptacle. But many of the ones that do have a second outlet on the module. Sometimes the module is kind of a rectangle and there’s an outlet on each end. So you do still have two outlets to use, although typically only one of them is Networked.
But you need to check this, because some of the cheapest modules still cover both the outlets in the wall receptacle but don’t have the extra pass through outlet, so you do lose one outlet when use those.
You need to read The product description carefully, because the picture doesn’t always show both sides.
Some modules also have an extra pass through for a USB slot so you can charge a phone or a tablet.
Other Features
Some modules do energy reporting.
A few modules are rated for outdoor use.
Zwave modules typically have a reset button on the outer case. If the button is on the front, it can usually also be used as a manual on/off, which some people like.
Some modules have an LED, but most of the older ones don’t.
Some have a USB charger slot. This is usually “always on“, meaning not controllable, but there are a few Wi-Fi power strips that do have controllable USB slot, particularly Meross. Here’s a typical Z wave model with a dumb USB slot:
brand notes
A lot of people have reported problems pairing the newest Aeon labs module. it’s just really fussy to pair that first time and some people report that it keeps dropping off the network . Probably has something to do with secure mode.
If you want Wi-Fi devices, check for safety certifications as many of the less expensive Chinese brand don’t have any. 
also check what amperage is supported. If you want to plug-in a small appliance, you probably want something that supports 15 A, and but some of the pocket sockets only support 10 A. those are best use only for table lamps.
Meross is a well engineered inexpensive Wi-Fi brand with good safety certifications, so that’s my personal favorite, but there are some other options as well. Often sold in multi packs which bring the price down even further. And they frequently have coupons on the Amazon product page. Available in both the US and the UK. Meross has an official smartthings integration, so no custom code is required. They have regular pocket sockets, outdoor models, and power strips.
https://www.amazon.com/Reliable-Support-HomeKit-Assistant-Control/dp/B084JML1WN/
This meross power strip has a group of USB slots which are all controlled as one group (on together, off together). The other receptacles are controlled individually through the smartthings integration.
https://www.amazon.com/Protector-Meross-Supported-Control-Outlets/dp/B07NBNJ32V/
Zooz is the house brand for The Smartest House and usually is the first to market with all the latest Z wave features. Well priced and well engineered, these are very popular in the forum.
If you are just looking for Zigbee repeaters, it’s hard to beat the IKEA Tradfri pocketsocket, which cost just under $10 in the US went back directly from IKEA. This is a simple no-frills single outlet pocketsocket, but is a very good Zigbee repeater and very well priced. no custom code is required. Available in many countries.
Other than that, all the pocket socket brands tend to get rated pretty much the same although they may have different features as described above.
references
Repeaters:
http://thingsthataresmart.wiki/index.php?title=Repeaters
Zwave vs Zigbee:
http://thingsthataresmart.wiki/index.php?title=Z-wave_versus_Zigbee