Developing your skills with an instrument isn't an overnight process. It takes months of practice to fully learn the basics, and years to master every aspect of playing it - and all that progress doesn't happen instantly; it's a gradual journey from the beginner to professional levels. With all that in mind, it definitely wouldn't make sense for an improving violist to move right from a beginner to a professional instrument. When you're well on your way and your skills start to surpass your first viola, it's time to look at intermediate violas like the ones found here to give you more room to grow without having to take the big financial and technical plunge of an advanced or professional model.
With as much variance as there is within the intermediate range for musicians, there's no single "one size fits all" viola here. Instead, it's worth your while to take a close look through the options to find the best individual instruments to meet your needs. For example, if you're still fairly new to your musical journey and planning an early upgrade, some good options would be the Bellafina Roma Select Series Viola Outfit and the Yamaha Model 5 Viola Outfit. Well-equipped and affordable, these instruments are the perfect first step-up from a beginner model.
On the other hand, if you're on the upper end of the intermediate range and looking for an instrument that's close to a professional viola, then the Knilling Heritage Viola Outfit or the Maple Leaf Strings Lord Wilton Craftsman Collection Viola might be more up your alley. These instruments carry a steeper sticker than the Bellafina and Yamaha models, but they deliver a higher degree of craftsmanship and build quality in return.
Having said that, any instrument in this category is a fantastic choice for an intermediate violist: it's just a matter of matching the best option to your budget and experience level. Those factors are ultimately in your hands to weigh out, and the decision is yours as to which intermediate violas are qualified to become your next instrument. Take your time and read up on each one that interests you, and the right pick is sure to stand out soon enough.