Hi Dan,
I own one property in Worcester and am currently looking to expand to a second. My experience has been good so far. You can definitely find much better cash-flow deals in Worcester than in other parts of the state. I own another property in East Boston. And the rental market obviously isn't anywhere near as rabid as Eastie (and the property is not going to appreciate like Eastie). So you don't necessarily have the same number or quality of tenants to choose from. But, we inherited one vacancy last fall and were able to fill it with a great tenant very quickly at a competitive rent. There is also lots to like about what is going on in Worcester from a development perspective. So I do think there is long-term upside potential (although, I never invest based on that -- its all about the cash flows for me).
I strongly agree with and echo the other comments on here, however, that location in Worcester is critical. And it can literally change by the block. So make sure you are working with someone who knows the neighborhoods if you don't know them yourself. I grew up in the area and have been living in a neighboring town for 3 years and feel like I know central mass like the back of my hand. But, I still don't feel totally confident figuring out the Worcester neighborhoods. I've worked with a very helpful realtor who does a lot of multi-families. I'd be happy to private message you his contact info if you like.
I'd also be happy to grab a cup of coffee or have a phone call sometime if you have more specific questions.
Until then, best of luck!
Jeff