Friis: It depends on what you intend! Aside from technical specs. (frequency, data rate, power, current drain, RSSI access,sensitivity, modulation schemes & error handling etc ) even "boring" aspects like module size, pin out spacing, budget, delivery time & supply voltage may influence choice.
"Horses for courses " !!
I've had a good deal to do with Dorji over the years, much of it PICAXE related. Most of my orders (as recently as March 2018) have been directly from their Shenzhen (China) base via their ever helpful Mark Yao. Mark then indicated that new LoRa modules, presumably using Semtech's SX126x new RF engine, were due for release about now.
As far as I know, Dorji are still active retailers - a quick Google shows
numerous products on their site. Here in NZ their "887" ASK receiver modules remain very popular educationally with diverse micros (RPi, PICAXE etc). Note - NZ & China have a free trade agreement which makes for extremely easy importing- we've no taxes levied on items valued under ~US$300 either.
For
duplex (2 way) 433 MHz work the budget & versatile HC-12 (not a Dorji product of course) admirably tends first choice. Rev. Ed may well want to favour it...
Ruthless technical progress of course continues,with low supply (~3V) modules personally appealing. However the increasing abundance of small,smart & cheap rechargeable 3.6V-4.2V LiPo packs makes even that incidental!
HopeRF's CMOSTEK RFIC based 433 MHz ASK receivers (below) tend favour for both low supply needs & their outstanding performance in marginal links. They seem to work with any 433 MHz ASK TX and UART capable micro -refer the Forum discussion from Nov. 2017.
Stan.