The Thirteen Primes are the template for the Transformer race and all female Transformers are based on her. She was also in a relationship with Megatronus Prime, which obviously didn't go as planned. Solus Prime created many of the more powerful and mystical objects in Transformers lore. Personally I think it's cool that they made her a more in depth character and didn't go down a cringe route like often happens with female characters.
Solus, like Prima, has a more fantasy themed appearance. I've always liked when robots are designed with similar cues. Egyptian, Easter Island, Mid-evil, and similar design elements make for an interesting looking character. Solus is pleasantly colored in dark purple armor with gold highlights on her grey robot parts. She's pleasantly articulated, you can even move her dress (is that a dress?) in sections to allow for leg movement. Her hammer can be held by one or both hands, though you'll have to disassemble it first. Solus Prime transforms into a Cybertronian Armored Truck, and that's unfortunately where things go south.
Transformation is not a pleasant experience at all. Honestly, it feels like the alt mode was an after thought. It looks cool, but the shape suggests they initially had something else planned. There's a few spots that feel over complicated for no particular reason. The arms, for example, form the front wheel assembly. By itself it's fine, but there's an odd flat plate in both shoulders that has to be folded into the truck body. I never noticed these panels in either mode and have no clue what purpose they serve. Fitting them into their spot in vehicle mode wasn't easy for my big fingers either.
Then there's the feet. the legs fold up into the rear section of the truck. Like the arms, that's mostly ok, but getting the feet to fold into place is pretty unclear and awkward. Even looking at the instructions, it just doesn't work until miraculously it just does. Of course you'll have to knead the toy a little to get everything to align properly after doing so. It just doesn't seem to work right. The biggest problem that's actually a problem and not subjective is various parts just kept coming off during transformation. The plastic grade on some joints isn't great and various places (like the knees on mine) pop out of place while you're folding them around. It's infuriating. Several others have complained about this online, so I can be assured it wasn't a case of clumsy fingers or QC issues specifically with mine.
Truck mode looks neat, though after the unpleasant transformation it'll take a minute to appreciate. The hammer can attach to the side. You'd think since it can be disassembled that the pieces would be distributed about the mode. That's another thing that makes me think the truck mode wasn't originally intended. She folds up into a shape and there just happens to be truck parts to put into place. The dark purple and gold highlights are dominant in the form and once again look great. It's a very neat looking toy, I just wish the less than stellar transformation didn't overshadow the positives.