Upgraded my Garmin Edge after years of mostly faithful service. Liked the 820 enough I got Edge mounts for my bikes and retired the various old wired and wireless computers, preferring to switch just one among them.

But the battery was losing capacity and display (or my eyes) was dimming so I upgraded to this latest edition.

What a difference. The new 840 is fast, acquiring GPS right after switching on and responding to buttons and screen swipes in real time with none of the 820's lag. The display, slightly larger, is super sharp, contrasty and easy to read—reason enough to make the switch. Micro USB is ditched for USB C and the cover seems stouter than the one that disappeared from the 820 years ago. There is a new pair of scrolling buttons, the rest of the layout is mostly unchanged.

I have not explored its many new features and capabilities--Garmin will mimic the old unit's setup when initializing the new one, so I'm using the same screens as before, including SRAM e-shifting display. I can finally read the graphic displaying chain position of the rear cluster.

Not a review per se but perhaps some insight to anybody considering the 840, whether owning a current model or not. I had pondered the larger 1040 for its big display but now know it was not needed for readability's sake.

Note: Connect still logs two rides from the 840 and my Fenix watch, which I use for heartrate, magically doubling my miles ridden. IDK why it doesn't resolve doing two identical things simultaneously--maybe there's a setting I haven't discovered.

I upgraded from a 820 to a 540 a couple months ago. Agree with your comments. Much quicker between screens (especially maps) and in picking up gps signal. Really happy with it. I like being able to configure in the app.

You should be able to broadcast your heart rate from your Fennix to the Garmin.

My Instinct watch sends HR to my 1040 (using broadcast HR). The HR data gets picked up as part of the ride activity and sent to Connect. No need to have multiple ride activities being tracked.

They upgraded the screens with the 830 generation of devices. I got my 830 prior to cataract surgery, and it was a big improvement. I recall the 820 still had some software issues that also went away with the 830.

Thank you so much. Works!

The 820 and the 520 were not among the better products from Garmin.

Garmin might have been feeling a little heat from Wahoo.

The 830 and 530 were much more solid. The 840 and 540 seem like solid follow-ups too.

The 1040 is functionally the same as OP's 540, but with larger battery and larger screen. Absolutely the finest cycle computer I've used, and the battery life is incredible even with the non-solar version. I got it for below wholesale pricing, but would be happy with it even if I had paid MSRP -- it's that good.

I presume you meant 530 in your first sentence. I agree that the 520 was a bit of a dog and the 530 was a huge improvement. I haven’t tried the 40 series Garmins yet, but I get the impression they are more of an incremental upgrade. Or are they much better?

Yes, 530. The 840 and 540 might be incremental upgrades, but they seem fine (they aren’t dogs) regardless.

The 1030+ was a fairly significant upgrade to the 1030 (even if it might have been incremental).

(I don’t know much about the 1040.)

Agree, the 1030 Plus got a lot of OS upgrades that they sadly did not send to the 1030, but why would they ?. I ended up skipping the Plus and got the 1040 on sale at my LBS. It's a terrific device.

I just placed an order for the 840 (BTD, gold, 25% discount today). Apparently one of the advantages over the 540 is double the space, so I can install Europe maps without having to remove anything. I have to make a trip soon, and hope to squeeze in some biking.