Any place is good to visit if you are in the area and every place has something to offer. In baltimore, stay at the inner harbor. I've never been to Pittsburg so I have no info there.

We've always visited Baltimore as days trips from DC, and a last minute road trip to Michigan from DC a couple of summers ago took us through Pittsburgh and Cleveland, both of which had interesting and worthwhile diversions. Baltimore and Pittsburgh offer art, cultural/historical, and food escapes, but I don't think I would I make either Baltimore or Pittsburgh a "must see" unless I was in the area or found an awesome last-minute airfare deal.

In case you forgot that you asked this question 5 years ago, I thought I'd include the link.

http://www.fodors.com/community/united-states/baltimore-and-pittsburgh-us-must-sees.cfm

HOw interesting!! But I'll just weigh in and say that when we have hosted people from Russia and China they found our off the beaten track fairly large city to be fascinating!! Just as we found small and large places in Europe to be exotic and interesting.
As an American, I wouldn't necessarily take my kids to Pittsburg or even Baltimore rather than MANY other places.

I lived in central PA for over 50 years. I never took my kids to Pittsburgh. DW and I went there once to take a flight out.
I took my kids to Baltimore to see the Inner Harbor attractions.
Both cities have great major league baseball parks.
Our daughter got married in Baltimore the Saturday before Memorial Day but we didn't go down to Inner Harbor then.
I can well remember when Pittsburgh was considered one of the dirtiest cities when the steel mills were still running.
It is just getting over its "Rust Belt" image.

Baltimore? I don't think so.

I read a travel article about 7 years ago touting Pittsburgh as being a great travel destination. Since we live within driving distance, we went there for a long weekend with our teenagers and had a wonderful time!

Fast forward a few years and DD is enrolled at the University of Pittsburgh, so we have a reason to visit more often.

We love that city. And, by the way, if you are a fan of "The Dark Knight Rises", then you might be interested to know that Gotham City is actually Pittsburgh. (A pivotal scene was filmed just a couple blocks from DD's apartment.)

Why not visit Pittsburgh?
See The Warhol, the Carnegie Museums, the National Aviary, Phipps Conservatory, maybe catch a Pirates or Steelers or Penguins game, browse in the Strip on a Saturday afternoon...take the big red bus to do your own hop on hop off with tour information, shop with no sales tax on clothing, so much to see and do.
And FTR, the city is PITTSBURGH, not Pittsburg. Very important information!

Why visit Pittsburgh, PA?
Informative article with many links:
http://www.nsbe.org/convention/convention/travel/why-visit-pittsburgh.aspx

I live near enough to Pittsburgh to visit often, but yet not in the city so I still have an appreciation for what it has to offer. It is supposedly the most livable city now that the smog from the steel mills is gone and there's a lot of history there. I agree with Gretchen. It would be interesting if you're not from the US or if you live near it. If I had to pick one city to visit I don't think that would be it though. That being said, there's a lot of good, valuable things to see and do in it.

I live in Baltimore and love it, but would not name it as one of the great cities in the US, attraction-wise.

However, there are two small, but very fine, art collections/galleries (BMA & The Walters), several homes of huge historical importance, the National Aquarium, great music venues, fabulous food and really outstanding theater. To me, the harbor is just touristy and commercial. Right outside the city, there are good places for Kayaking and rafting.

Haven't been to either city yet, though there are a good 3-4 day's worth of attractions in Pittsburgh:

http://www.frommers.com/destinations/pittsburgh/2518010029.html

and a surprisingly large number of attractions in Baltimore, about a week's worth:

http://www.frommers.com/destinations/baltimore/138_indattr.html

My hope is that I'll get to both one of these days.

Whether either is more of a "must" than New York, San Francisco, Chicago, New Orleans, Washington DC, or Boston is of course another question.