i have both kinds of amps. my amps without a loop get everything in front, and i use the amp clean. amps that are multi channel, where i use the amp gain for my distorted sound, i use the loop for time based effects.
here are a couple rig examples that i have to use:
1. my vibro champ get used with an old roland GP-8 rack unit. it and the head are rackmounted the roland goes into input one, and i get all my effects from it. the amp is used to amplify the effects.
2. my egnater tweaker has a loop. it is one channel so i get a cool tone and then put my boss ME-70 in the loop for time based effects. sometimes i set the egnater to sound like a "vintage" amp, and then i run the ME-70 in front and get all my sounds from it. then the amp is used to amplify the effects.
3. my rivera S120 has a true stereo effects loop. i use it with multiple cabinets in a wet/dry set up. i will take my rack, which uses a digitech quad (4 channel effects processor), and plug the effects into the loop. depending on which patch i select for the channel i am using (clean or distorted), the patch will send effects to either amp A, amp B, or both. for example, for my clean sound i will use a chorus, a reverb and a slight tape delay. in this case the chorus and reverb are routed to both power amps while the delay is sent to amp B.
the carvin vintage 16 is a nice amp. if you intend on using a lot of effects with it, i would suggest you run a set up like example 1.