When I was installing Go Launcher this past weekend, I noticed that the developers also had an SMS program, appropriately titled GO SMS Pro. So, since I was feeling adventurous, I decided to try it out.
I had finally caved a few months ago and installed Handcent SMS since, which the default messaging program is adequate, I text a lot and I was finding I wanted a few more features and customization options. I haven't had any problems with it, so trying something new wasn't because I was unhappy. I really like all the options Handcent offers, and to be honest, my only gripe with it is that the theme I'm using doesn't have a background for when the phone is rotated. All my fonts are set up for a light background, but when I rotate the phone, I can't see anything since it's now against a dark background. It's a minor issue that isn't Handcent's fault so much as me just not getting around to fixing it, so I don't hold it against the program.
GO SMS is, for all intents and purposes, the exact same program. It has some different themes since it's from a different developer, but honestly, I felt like I was using a clone program rather than something different. Even the menus for customizing felt and acted exactly the same. There might be some minor differences, but if there are, I couldn't find them. However, GO was lacking a few features of Handcent that I like, such as the picture of the person next to each message. I have some long threads, so it's nice to be able to tell at a glance who sent what.
I had already uninstalled the GO contacts manager, which I installed at the same time as the others, because while I LOVE the ability to sort by the groups I have in my Google account, there was just way too much lag. It was taking upwards of 60 seconds to load my contacts every time, even to get into the dialer. So it had to go. And with being unsure if I want to stick with GO as my primary home launcher, to be honest, there wasn't anything keeping me with GO's SMS program. I just felt like it doesn't bring anything new or exciting to the table.
My Verdict: GO SMS Pro is essentially a Handcent clone missing a few features that aren't major, but if you use them, it stands out. If you're not already using Handcent, and you have other GO products, this is something to check out, since I did like that you can theme all your major programs to look alike. However, if you're already using Handcent, even if you are using other GO products, there really is no compelling reason to switch.