A comparison of these two shavers since both are Bluetooth-enabled and use Philips' GroomTribe app. Both are actually excellent rotary shavers as far as performance, and both are fairly recent (within a couple of years) shavers in Philips' lineup. The GroomTribe app itself was released in Jan 2020. We’ll get back to the “why” of a shaving app later, but these shavers are among the limited number of PN’s shavers that use an app to both coach shaving technique and control the shavers.The S7940 is the more “conventional” Philips shaver, with rounded heads and a detachable trimmer. The S7782 has a distinctly “squared off” look, and a flip-top head as well as an integral trimmer harkening back to the early days of Philips rotaries. The S7940 uses the dual-cutter SH70/52 head with specially coated “Anti-Friction” rings. It provides a fairly close shave, and actually feels similar to the SH98/72 head of Philips’ flagship Series 9000 Prestige shavers. The S7782 has a single cutter head inside the combs, the SH71/52, which to me provides a slightly closer, and actually more comfortable shave than the S7940 dual cutters, and uses something Philips calls "ComfortGlide" rings. These comments are confounded by the fact that any of these heads (20mm cutters and combs) are interchangeable among any of these shavers, so my observations are just for the shavers as they come out of the box. If you like the form factor of the S7940 but prefer the SH71/52 heads, you can swap out and have the best of both worlds.As far as the shavers themselves, the S7940 is the smaller shaver (partly because the trimmer is not integral, and partly because the head of the S7782 is larger and bulkier, and it’s an inch or so longer). The S7940 is also lighter - 5.9 oz without trimmer - compared to the S7782’s 7.1 oz. The complete shaver heads themselves are also different – the 7782 has the “angular” heads of the 7100/7500, whose function is a little obscure to me. You can’t practically get much closer as far as shaving around corners, like your nose for example, and actually the angular heads are considerable wider in one dimension of the ComfortGlide Rings, being about 5.5mm wide before you actually get to the edge of the comb and cutters. The thinnest dimension is about 4mm from the comb, compared to about 5mm for the standard round Anti-Friction rings of the S7940, but the practical application is that the design of the S7782 heads doesn’t provide any better access to the cutters in general as far as getting closer to ear or the nose for example, and in some cases keeps the cutters farther away, and manipulating the square heads around your round face can be challenging, particularly with the increased height and bulk of the head overall (S7940 - 58mm wide, S7782 - 65mm wide). I expect the design was just cosmetic rather than functional, but that said, it’s a fairly close match as far as close and even shave for all areas between the two, and with practice could be dead even. The coated rings around the combs/cutters of both shavers actually do provide a more comfortable shave than the conventional rings around the combs of other rotaries. The flip-top head for cleaning on the S7782 and the integral trimmer address some of the issues with some users that disliked the pop-off heads and separate trimmers of other Philips models, although the integral trimmer doesn't seem quite as effective as the removable one, is a little flimsy and can practically be used only in one direction (the removable trimmer doesn't flex and can be used back and forth).The cleaning systems are very different, but use Norelco’s same cleaning solution, which is excellent at cleaning and lubricating the shavers. The S7782 uses the Quick Clean Pod, which is just an unpowered receptacle for holding a small container of the solution and is powered by the shaver itself. It runs for a minute and seems to do a good job, but doesn’t recharge the shaver – in fact it uses some of the shaver’s charge (looks like about 1 percent per cycle). The SmartClean station used by the S7940 both cleans and charges the shaver (but is air dry only), but the SmartClean Plus (which also fits the shaver) dries it with induction heating as well. The Quick Clean Pod is drip-dry only, and you may find some of the areas wet the next morning after running it following the previous morning’s shave. The SmartClean station is taller and bulkier, but eliminates the need for a separate charging stand as with the S7782 (which could just charge periodically with a cord, but that sort of eliminates the “convenience” part). Cost is another difference, with the S7782 being about $20 cheaper than the S7940, including accessories.Back to Bluetooth – the Philips’ GroomTribe app (iOS and Android) connects to the shaver (only one shaver can be connected), and records the duration of the shave and the percentage of time you used a rotary shaving motion (which increases the efficiency of a rotary shave) - although the app seems to be quirky recognizing the S7782 as far as product info, and the "rotary motion tracking" for the S7782 seems to be off quite a bit. You don’t need a phone beside you, it will download it later, unless you use the app to provide guidance while shaving. Which is possible, like having your own shaving coach. It also provides battery info, and has a library of shaving tips. The downside for both shavers, and I’ll call it a negative, is that the app is the only way to control the speed of the shavers, unlike some of Philips’s other models which allow adjustment on the shaver itself. Regardless, I actually found the app useful, and thankfully either shaver works just fine without any connectivity as a standalone shaver. The S7782 does have a conventional LED screen that provides most of the info you need, like battery charge, rotary motion, lock icon and cleaning reminder and indicator when it's actually cleaning, but the S7940 is a bare shaver - all of its info is in the app except for the lock icon and cleaning reminder. I found both shavers to be great additions to Philips’ line of rotaries, and recommend both if you’re looking for a mid-range high end, comfortable and close rotary shaver, with the nod for convenience going to the S7940 (one stop charging and cleaning) as well as maneuverability, and cost, comfort and closeness going to the S7782 by a whisker with the SH71/52 head.