The Palm Report –
Pros:
- Form factor is perfect size for a cycling GPS
- Build quality is top notch
- HD screen resolution is bright and sharp
- Runs Xert mobile like a charm
- Play Store apps for whatever else you want
Cons:
- Battery life
- Battery life
- Battery life – 800mAh!! WTH were they thinking?
- No ANT+ without a dongle; but BLE works fine for me (HR, cadence, smart trainer, and power) .
- Doesn’t provide the all-in-one solution as hoped for (phone as GPS); I won’t bother to install a SIM.
Tested with XM (v3.5.2.0) running in foreground continuously at normal screen brightness –
2 hour rides/workouts, no problem. 2-1/2 hours is risky. Anything longer and you need a battery power pack of some sort but NOT the over-priced, under juiced Mophie available for the Palm.
I came up with an 8+ hour option (as pictured) but haven’t tested that runtime estimate. The longest route I might ride on a weekend is 6 hours.
No doubt you could extend runtime considerably with apps that support sleep/dim functions and operate in background. Possibly 50% or more? However, I am baffled how Palm came up with 4:45 hour estimate for a “GPS workout”. Doesn’t seem feasible with any app and sensors connected.
Haven’t tried removing Verizon bloatware to boost battery life but that should help too. I did disable most apps under Settings for my tests.
Summary –
Palm works fine for me as a cycling computer, but I’m only interested in running Xert mobile with BLE sensors and Google Maps when needed.
I assume Varia radar will work but haven’t purchased a RTL515 to test that yet. Hint to Xert: Add radar support in future version of the mobile app. 
Total cost: $150USD (refurbished Palm + TPU case + VHB tape + 6000mAh power pack + glue on quarter-turn plate); 185 g
$150 is my do-over price. I spent more initially but got refunds when I realized where things were headed. The first protective case I got (polycarbonate frame, TPU bumper) couldn’t be used with the power pack because it’s too stiff to mount with VHB tape and be able to remove the phone. However, I kept that case to use as my “2 hour” solution (indoors or out). It’s a slick looking combo:
If your workout/ride needs are lightweight in nature (1-2 hours) this is the way to go (refurbished Palm + SUPCASE + KOM adapter plate = 88 grams, $128USD).
For the 8+ hour solution (first two pics above) I got a 100% TPU case which is flexible all-around so the phone can be pulled out even with case securely VHB taped to the power pack. This TPU case happens to accept a lanyard loop so I made use of my Garmin strap. If I were to redo this configuration I would get a slightly smaller power pack (same design, different manufacturer, 5000mAH).