Picking a pro lab to print your photos can be a daunting task. Do a quick google search and you'll see what I mean. You can try all the services yourself and pick the best one for you, or read reviews of people who actually used the service and trust their opinion. If you happen to print a lot of images in a year or maybe a really important project deadline is on the horizon, it might be worth the investment to purchase prints from several different labs to see what works best for your images. For me I have tried several printing labs over the years including products such as photo prints, large giclee prints, metal pieces, acrylic face mounts, calendars, panoramic prints etc... I always recommend using a pro lab to print your images. Pro labs will produce better images with better quality printers and media. Labs found at places like Walmart, Target, Costco, Snapfish are great places to print out your 4x6 vacation photos, but I wouldn't trust them with "frameable" work. These labs in my opinion don't produce professional quality images. mpix lab was the first pro lab I used. The prints were good, they were packaged and shipped using sturdy materials. Overall they are a good. They are probably the fastest lab I have dealt with. Most cases your order arrives at your door in a couple days after ordering. Their main photographers is that of the wedding genre. They provide many products that the bride will adore. They are a good overall lab. Doing many things good!
Image Wizards is known among the pros as the best place to get your metal prints made. They were also one of the first companies to do metal prints. Since the fad has reached the mainstream, most other photo labs now offer metal prints. With that said, Image Wizards have a step above of them all in terms of quality. This is what they specialize in and have perfected the process. This is who I use to get my metal prints made.
APC(artistic photo canvas) is similar to Image Wizards, as in they are a specialist printer. They specialize in canvass image printing. They use better materials than most other canvas photo labs, and the canvas prints are top notch. Canvas prints aren't my favorite media but If you like canvas prints I would go here.
WCI(West Coast Imaging) is probably my favorite lab. When I look to do an acrylic face mount these are the guys I turn to. They require a minimum order and prices are a bit higher than the other labs, but they make your images look the best they possibly can be. If you have an important client or a gallery opening, you need someone that will show attention to detail and make your images stand apart. This is what WCI does. Your photos will have never looked so good.
Aspen Creek Photo is the sister company of WCI. They use the same papers, printers etc, but the process is more automated and a bit cheaper. They still make great quality prints, but they aren't studied over by someone like at WCI. There is no minimum order and they have competitive prices of that of the "popular" labs. Again it's one of my favorites.
Bay Photo is another great lab. It's between Bay Photo and Aspen Creek as my second favorite. They print out great looking images and have very competitive rates including shipping. As I write this, any order over $12 ships for $1.50. I had a bunch of calendars made by them and the quality was great. There were some minor problems with some of the calendars, some were my fault and some theirs, but they have great customer service and they corrected the issue. That tells me they value their customers and the quality of the output.
These are my labs of choice. If I can't print it at the office, or if I need something printed on metal, canvas, acrylic, etc.. these are the guys I turn to. What are your favorites?