There are two ways of sending group texts: as bulk texts (the same text sent to a group individually) or group (the message sent to the whole group). The first sends a set of SMS, the second sends an MMS to the group.
So whether everyone sees replies depends on which one you are set up to send, or which type the original sender sent. You can't do anything about other people's settings, but you can check yours. My guess, from what you describe, is that you are set up to use bulk SMS, which go separately to each individual.
The pros and cons do depend on your tariff: in the UK where I am SMS are generally free, or effectively so (so many included in your tariff that if they aren't unlimited they may as well be), but depending on your service provider MMS can be quite expensive. Most people i know use internet messaging apps rather than MMS for group messages.
You might hope that RCS will fix this, but only some service providers support it at present, and of course Apple refuse to have anything to do with it (presumably since it would eliminate most of iMessage's advantages, and so if adopted cross-platform would remove a "lock in" for their users).