Part of the reception issues most likely boils down to your handset in question as most modern flip phones don't always have the greatest antennas or broadcast strength. Atmospherics can impact
any RF reception, but the level of problems you're having sounds more like a phone issue than a network issue. If you're in a dodgy reception area, research the available handsets through sites like
GSM Arena and
Phone Arena to find detailed specifics on broadcast and reception strength. Look over general reviews online as well as
C|Net, which has some decent reviews.
The only MVNOs that really have off-network roaming (beyond PagePlus) are the postpaid outfits like Ting and Consumer Cellular. As for the reason why I don't really include Consumer Cellular in the mix... they present their billing in a slightly murky manner to really make their prices clear. Let me show you a breakdown of their actual tiered fee structure so you can better compare the price of the services with traditional prepaid MVNOs and Ting:
$10 a month per handset (minimum monthly fee)
25¢ per minute overage from plan
10¢ per SMS overage from plan
1¢ per kB overage from plan
$5 for 100 minutes
$10 for 300 minutes
$20 for 700 minutes
$30 for 1200 minutes
$40 for 1800 minutes
$50 for 2400 minutes
$2.50 for 100 messages
$5 for 500 messages
$10 for 1000 messages
$20 for 2000 messages
$5 for 2MB data
$10 for 15MB data
$20 for 30MB of data
When you factor in the issue that you have to manually switch between plans to keep away from overages and the rather expensive rates they charge (which isn't unexpected for an AT&T postpaid MVNO with T-Mo roaming), there's just not much worth spending time on them as they're a bit
too niche... plus, I wholly approve of not giving any money to any outfit that takes such an insulting and condescending stance on prepaid MVNOs and are willing to hire
Ron Maestri to do commercials. ;)
They may be fine for people who's low usage, road warrior wandering habits and predilection toward GSM service warrants it... but you can see how quickly the rates can skyrocket well past even traditional MNO plans even from AT&T directly for heavy users, and they're deliberately structured to automatically try and reap overages from users who might exceed their assigned plans.
You might want to check network coverage maps for your area between CDMA and GSM carriers as well and ask friends and family who are in the area or visiting how their reception is where you are. Though typically rural areas usually have better AT&T GSM coverage than any of the others, exceptions do occur.
An option for you to potentially look into if you have decent Sprint coverage in your area might be going with a CDMA outfit like Ting and taking advantage of their new
BYO(S)D program, and locating an unlocked and clean ESN Sprint branded
Motorola XPRT CDMA/GSM World Phone and grabbing an Airvoice Prepaid SIM card for fallback GSM service at around $3.33 a month. You didn't mention monthly costs or usage levels, but a setup like that would run you around $25 a month between Ting (500 minutes/100 SMS/100MB - $21/month) and Airvoice (Pay As You Go - $10 every 90 days - effectively 70 minutes or messages in 90 days)... this would effectively give you Sprint as your primary network, Verizon as a fallback roaming network, and AT&T as an emergency fallback network.
That's the best suggestion I can make given the limited info provided. Hope it helps!