Subway is one of the largest global chains, but its ubiquity hasn't necessarily led to an overly positive public opinion.

I'll admit that I've been let down by the restaurant more than once, but nonetheless, I count myself among its fans. Because Subway has over 30,000 locations globally, it's still nice to know I can probably grab something familiar at one, no matter where in the world I am.

I ordered a 12-inch roast-beef sub for $16.28, which breaks down to about $1.36 an inch.

Subway employees can sometimes go a little heavy on the sauce, but the few stripes of mayo I got were well-portioned.

The bread and cheese were nothing special, but the roast beef was actually pretty tasty — I just wish there was more of it.

The produce truly stood out here. The tomatoes were thickly cut and actually had good flavor, and the lettuce tasted fresh and crisp.

I'd argue that roast beef should be the star of a roast-beef sandwich, but I'm certainly not mad at the Subway sub.

Jimmy John's is a Midwest staple that's spread to over 2,000 locations across the US. It's perhaps most famous for its fresh-baked bread.

I ordered a regular (8-inch) Big John but paid $1 extra to add provolone cheese. The total came to $11.41, or about $1.43 an inch.

Sadly, I thought my roast-beef sandwich from Jimmy John's tasted rather bland overall.

It needed a bit more meat, the meat needed a bit more salt, the cheese was all but undetectable, and the veggies faded into the background.

You'd think that would mean I didn't enjoy this sandwich, but that wasn't the case because of one thing: the bread.

Jimmy John's French bread is good enough to be enjoyed on its own with just some butter or perhaps a spread of Dijon mustard. It readily elevates what would've been an underwhelming sandwich into a perfectly decent meal.

New Jersey-based chain Jersey Mikes has over 2,000 locations throughout the US and Canada.

It's famous for building sandwiches with freshly sliced cold cuts, and it was the only chain where I watched an employee slice my roast beef seconds after I placed my order.

My No. 6 (roast beef and provolone) 7-inch sub cost me $12.36, or about $1.77 an inch.

The roast beef piled onto my Jersey Mike's sandwich was well over an inch thick. I pulled a few pieces of meat out to try on its own and found that it tasted high quality, too

The provolone cheese also had good flavor, but I didn't think there was enough lettuce, and the tomatoes tasted a bit bland.

However, the biggest issue I had with the sandwich was the rather sloppy, messy assembly. It was difficult to hold together as a cohesive unit, and the mayo was slapped on too heavily and unevenly.

I haven't ordered this enough to know if it was a one-off problem or a consistent problem with the chain's sandwich assembly.

The generous portion of roast beef and the quality of the meat at Jersey Mike's easily would've made it my favorite sandwich had it been assembled with more care.

However, as it is, there were things I liked and disliked about each sub. Jimmy John's sandwich tasted pretty bland despite its amazing bread, and Subway's felt underfilled but had lovely tomatoes and lettuce.

It would be divine if I could combine the meat from Jersey Mike's and the produce from Subway on the bread from Jimmy John's.

The foot-long sandwich came to $11.89. When combined with the other items, my total meal came to $17.17, not including taxes and fees. 

I decided to compare the sandwiches alone since I couldn't order the same drink or chips from both chains.

I thought the sandwich was a good size for the price.

The 6-inch sub would have been more than enough to satisfy me for lunch, but I was happy the sandwich was large enough to split with a friend or for me to save the other half for later.

It definitely looked like a lot of care went into crafting the sandwich to ensure that each bite contained all of the ingredients.

As I predicted, I could taste every part of the sandwich in each bite. The ingredients, especially the lettuce, tasted fresh, though I thought the tomato slices could have been a little thicker.

There was a lot of sauce slathered on the sandwich, which I liked, and the mustard added a lot of flavor. 

However, I thought the bread felt on the lighter side and didn't have a lot of flavor to it.

The sandwich came to $13.69, making it a little more expensive than the sandwich from Subway.

I also added chips and a drink, so the entire meal cost $21.57, putting it at $4 more than Subway's.

The two sandwiches couldn't have looked more different. Whereas the Subway sandwich (pictured left) came on flat-looking multigrain bread, the bread Potbelly used was crusty and appeared to be of a higher quality.

I was excited to see how the actual taste of the sandwiches would compare.

The ingredients were laid out less methodically, and I worried that each bite wouldn't include all the ingredients at once, which is what I prefer.

There was also a generous serving of lettuce, onions, and tomato that really helped make the sandwich stand out. However, I thought it was a little light on the sauce — I couldn't really taste the mayonnaise or mustard.

The sandwich delivered on price, size, and flavor — and I loved how they weren't afraid to hold back on the sauces.