I went to Stella for the first time tonight, and ordered the spaghetti and meatballs. I was quite surprised -- the pasta was limp and boiled for too long. It was saturated in overcooked tomato sauce (sorry, I mean "sugo di pomodoro"). The dish should have had less sauce, with a brighter, cleaner tomato flavor. The meatballs were okay; I could tell that the meat was high quality from the supple texture but the meatballs were very plain-tasting. Perhaps garlic frightens the rich.
I have to say that I was excited about trying Stella but disappointed when I ate there. The room is quite romantic (if you don't mind loud music) with a wall of windows overlooking Blackstone Square Park. The white decor recalls a chic restaurant in Miami or New York. I'm willing to pay $17 for a spectacular pasta. I went to see fireworks and found a wet match.
I think Stella aims pretty middlebrow; its formula is doing unchallenging Italian-ish food in a swank setting at reasonable prices for the South End. I've had that spaghetti dish when it wasn't oversauced nor the pasta overcooked, but doing it the way you had it may not be a kitchen mistake. (There are pastas I prefer there: the orecchiette, the other spaghetti.)
I find it's a reliable crowd-pleaser, the kind of place where I can take unadventurous diners and they'll be happy; people love that room. I tend to stick to the apps, pizzas, and pastas, though a couple of the entrees are above average, like the cioppino. I think the fact that the menu largely never changes, year in and year out, says something about its appeal: Stella's customers want something familiar.
I like the back-room bar on weekends, which has a great bartender and is less frenetic than the main bar. The late menu, which has most of my favorites (but no secondi) is served every night till 1:30a, also handy. But Sage up the street a far better bet for innovative Italian cooking, and they have a small-bites menu of fairly simple dishes that I think is much more interesting than Stella's.
re: MC Slim JB
I'd have to agree with MC. I've been there for a girls night out - for wine (although their selection isn't necessarily large) and to split some appetizers. I did really like their mushroom pizza and the orecchiette. There's nothing there that's necessarily outstanding but people seem to have a good time.
I was unimpressed by my one visit to Stella, and never quite understood it's standing, but to each his own. One of my main gripes is their choice to use the most uncomfortable chairs I've ever had the misery of sitting in. I know you don't want folks to linger, but I don't want to throw out my back eating overpriced mediocre Italian.
My one experience there was reasonably enjoyable. Decent bar service, good apps., and tasty pizzas. Would go back, but probably at someone else's suggestion.