I have yet to hear a lav that has the same sound in regards to depth and fullness of a boom. The lav is a mixed bag. Yes, you can get it close to the talent on wide shots where you can't get a boom close enough. However, because of positioning as well as trying to get a more open sound, most lavs used in film are omni. The downside is as an omni, the mic is picking of sound equally in all directions and presents a sound different from the more directional and "present" sound aquired with a boom.
There is no better way to capture dialog than with a boom. Lavs are used as a distant second when booming cannot be used. "Reality" shows typically use lavs because of the unpredictable nature and the amount of wide shots being used. And the sound of reality shows reflect this.
Using lavs effectively requires even more skill than booming. Lav selection, placement and the ability to eliminate clothing rustle (without deteriorating the sound quality) are skills that are developed with lots of practice. Since there is no such thing as the perfect lav, most sound people carry an inventory of different lavs with different characteristics to match the situation, talent's voice, and placement options. Wardrobe selection greatly affects how well lavs can be used and this includes fabric choices.
Then there's the problem if mixing lavs when dealing with recording to only two channels. More and more sound people have migrated to multi-track (iso) recording systems to help address the limitations of using lavs. When sending the lav mix to only one or two channels, any RF hits, clothing rustles, or other aborations will taint the entire audio track, as opposed to using iso tracks where one lav's problem is isolated only to that lav's channel on the multi-track.
Each location provides unique challenges with regarding to selecting frequencies. Channels used successfully on one location can fail in another location. Frequency selection can be planned somewhat ahead of time, but I typically check these choices with tests once I hit a location while talent is in make-up and make any needed changes before wiring the talent.
It can sometimes take 5 minutes or more to properly wire and check talent. It takes experience to look at the talent's wardrobe, listen to the talent's voice, and quickly determine which mic to use, where to place it, attach the mic, set input sensitivity based on the needs of the scene and the talent's level envelope, select a place for the pack which will be hidden from camera angles, route and attach the cable, and then check for noise. If there are 3 actors in the scene, that's 15 minutes for the lavs.
Then there's the costs. I am using the Sennheiser G3s which are considered the least expensive wireless systems dependable enough and with good sound quality for serious work. I currently carry 3 and hope to add a 4th by the end of year. The transmitter, receiver, and stock mic cost $600/channel. Since the stock mic sounds a little harsh compared to other choices, I add an Oscar Soundtech to each channels mic inventory. Mics, attachment hardware and cases for transport add another $200 to $300 per channel bringing the cost close to $1k/channel.
Add production mixer, multi-track recorder, iso cabling, monitoring, bags and cases I've got about $6,000 invested in the rig to support 3 channels of wireless, plus the years of experience learning how best to apply this hardware to a shoot.
I'm a bit biased, but the fact that you can hire me out for less than $400/day with full kit, including all that wonderful wireless lav stuff, that useless boom, shotgun, hyper, blimp, windjammer, harness, and incredibly warm and welcoming personality makes location sound people a bargain.
But I forget, you're going to do this all by yourself. This is the last time I'll say this to you:
Filmmaking is a highly collaborative artform. The reason there are so many people on a crew is because each craft is highly specialized requiring years of experience to become proficient, and there is simply not enough time in a person's lifetime to become great at each aspect of film production. The next time you look at a behind the scenes clip. Look for the gray hair. You're looking at people who have committed their lifetimes to honing their craft in a particular area. My best advice is to find an area of filmmaking you are most passionate about, and focus on that area, then find others who are committed in other areas. There is no shortcut. There is no I in TEAM, but by rearranging the letters you can spell MEAT.
Over and out!