I've compared the Aspen to the G5s fairly extensively. As some may be aware I already have the G5 ADI and I'm slated to install the G5 HSI along with GAD29B in March.
The failure mode issue is significant. Without two Aspens, you're looking at a screen failure knocking out all of your primary flight instruments (assuming you replaced them with the Evolution EFD1000). And as noted here an invalid ADC input has the potential to brick one, two, or all of your displays, assuming that input is shared across the units (pitot for example.)
Dual G5s are a simpler, less feature-rich product, but frankly that is best viewed as a strength when you consider the kinds of airplanes these units are being installed in, and the mission applications they might encounter. They are very robust; their reversionary mode, though manual, is completely independent; and the user is required to keep ASI, ALT and VSI (if installed) along with a backup AI or TC.
They are extremely reliable, very easy to use, and supported by Garmin, who isn't going anywhere.
That alone was enough to sway me to Garmin over Aspen, but there are other reasons, too.
- In terms of out-the-door-price, it's really not a quick and straightforward comparison between Aspen and dual G5s. Aspen sells lots of upgrades and modules, including AP interfaces, and those modules and interfaces are generally quite expensive unless they're being offered on special. And the VFR version of the Aspen at $4,000 is probably a little below the dual G5's total package featureset; you have to bump up to the EFD1000 software ($10,000 total, approx.) to really compare them. The EFD1000 package turns the Aspen into a more feature-rich competitor, with various enhancements such as HSI overlays and etc. The VFR-only version doesn't even include an HSI, and, well, it's for VFR. Not very useful for most of us considering this product. So you really need to compare the EFD1000 to the G5s. That's more like $10k hardware vs. $5k hardware.
- But that's without Aspen's EA100 autopilot interface which is a whopping $2500 vs. the GAD29B from Garmin, which is $700. The installation price also seems to favor the G5s, as Aspen-authorized vs. Garmin-authorized seems to be two different price points in my experience.
- You can install the G5s as your budget allows. I did the ADI to see how I liked the hardware, and about a year later I'm doing the HSI. It's nice to break up the installation costs.
- Finally, the G5s are designed to work with the GFC500 autopilot. If you're fortunate enough to get your aircraft added to Garmin's AML, this alone is easily worth going the G5 route. This is going to be THE autopilot to get, and the G5s drive it. You're talking vertical nav, altitude preselect, flight director, ESP, the works. For $6k!
When I did this calculus early on my reaction was to be very concerned for Aspen's well-being, not to mention their ability to support their customer base into the future. Aspen's product line is
old; other than some software modules and upgrades being released for the EFD1000, this is a product which received its FAA certification in 2008 and hasn't been touched since.
In my view Aspen either needs to release a new product with groundbreaking new features for a compelling price (which is only possible if that product has been in R&D this whole time)
or drastically reduce the price of the EFD1000. I'm not talking a $4k VFR-only product, I'm talking a $5-6k totally loaded EFD1000 and a $700 EA100 AP interface, and even then I'm not sure it's really worth throwing your eggs in Aspen's basket.
They have to compete with Garmin, who has built an entire ecosystem of low-cost, ultra-capable products for the GA fleet. EVERYONE is going to want a Garmin panel. I've built mine around a GTN650, GTX345, dual G5s and, eventually, the GFC500 autopilot. It's going to maintain the highest residual value possible for your airplane and give you the biggest bang for the buck.
So when you look at the whole package, don't get distracted by a handful of features the Aspen has today which dual G5s don't. They're pretty minor things, really; format changes, overlays on the HSI, that sort of thing. Stuff I don't use anyway to be perfectly honest.
Look at the big picture, and it's a pretty compelling argument to stick with Garmin. That's my .02.