I think it really depends on what you're looking for.
If you want gritty, realistic sci-fi or military drama, forget it. You won't get that.
If you want Whedonesque character development and weepy performances, again, forget it. Not gonna happen.
I think the Star Trek analogy is quite apt, actually. There are some thru-lines in the stories, and plenty of linked episodes, but much of the time you have "monster of the week" things that sometimes end up building towards more. The first few seasons do gradually improve in terms of expanding the universe and building up the lore of the show which gets used later. Not exactly a plot line, but more just building on the richness of the experience.
However, you definitely have your redshirts, and your hero shields (most of the time). You have your funny episodes, and you have your more serious ones.
The show doesn't generally take itself TOO seriously, although I suppose towards the end of the entire run you get some pretty interesting stuff with the Ori. It's a long wait to get to there, however.
Oh, another Star Trek feature is that, somehow, everyone speaks english. That's more just a convenient cheat because otehrwise each new planet would need, like, five episodes before Daniel would even figure out how to communicate with them. I give them a pass on that sort of thing.
There are definitely weaker episodes here and there, though. And there are stronger episodes. There are bottle episodes, and filler episodes, sometimes being the same thing. Although some of the bottle episodes DO develop the characters in ways we wouldn't otherwise get.
Basically, my advice is this. If you go into the show expecting a Star Trek kind of experience, on the whole, you'll be happy. If you go in expecting Lost or 24 or even BSG, you'll likely be disappointed. SG-1 is very much a show stylistically rooted in the tradition of Star Trek, especially TNG, but with (most of the time) a budget and f/x from the '00s. It does build over time, and the show's universe gets considerably richer and more interesting over time, but if the general episode-to-episode experience of a show like TNG isn't what you're looking for, then you should probably skip the show.