Having played a few other RPGs on the DS, I now count Sonic as one of my favourites. The combat is fun, the plot is interesting and I appreciate the fact that there are dialogue trees rather then screen after screen of never-changing text. It doesn’t require mindless grinding and lasts an acceptable length without wearing out it’s welcome - which is nice considering that some other RPGs on the DS keep going on and on long after they stopped being fun.
There are several sub-quests, but they don’t have much of an impact outside of ‘find the hidden characters’. Still, they are standard Bioware fare.

The combat itself is a fairly standard turn based style, where you and your adversaries line up and take turns at hacking bits off each other.
But to keep it fresh and give the game some 'Sonic' speed, Bioware have made a slight tweak. This game’s equivalent of any other jRPG’s spells are called ‘Pow’ attacks. They can hurt your foes, heal your friends or allow your teammates to work together and deal massive damage. To pull off a ‘Pow’ attack you have to complete an ‘Elite Beat Agents’ style quicktime event that will determine the success or strength of your action. Likewise, if your foe tries a special attack you can attempt a quicktime event to stop them.

My one gripe is that the appeal of ‘build your own team’ is totally undermined by the requirement to use the ‘default’ team if you actually want to explore the play areas. Don’t like Big the Cat? Stuff you - ‘cause you’ll have to have him and his special skills to explore some specific areas.

It’s quite interesting playing a Sonic RPG, if only because Sonic has been in a lot of bad games. A lot of bad games. And it’s a minor miracle that this is not one of them. You see, not until this game did I find out that there are 'Sonic Fans'. Like, actual fans of Sonic's world. They are like Star Trek fans... only stranger.... and much more creepy. Bioware have crafted a story that manages to remain respectful to the source material, but also be well-written and intriguing to Sonic novices.
Sadly, the Sonic setting does distract from the game overall. Events that would come across as dark or sinister in a ‘standard’ RPG setting come off as boring when played out with cutsie animals. There are some scenarios that could have been quite interesting in another setting.
Likewise, the dialogue is good (and occasionally witty), but is ultimately shallow. It doesn’t really have any effect on the actual game or relationships. And then there are the inter-personal issues that are touched on and then brushed over in the name of being family friendly.
These things are all disappointing from a Bioware RPG, but are understandable given the setting and target audience.

Overall, this game shows a lot of promise, but it won’t go down in history as one of Bioware’s greats, and it makes me wish they had gone with one of their own franchises for their first DS outing.
It’s a very competent DS RPG - but Bioware fans may be disappointed at what is obviously a ‘child-friendly’ offering. If you don’t mind that and you’re looking for a portable RPG, then it’s a solid buy and a fun way to kill some time - even if it’s not an RPG classic.