n theory I would agree with you as long your project is supposed ton sit on a table and has a power supply hooked on the wall.
Personally, I prefers this little module, that is about the size of a finger. I don't use it with the shield so it's very very space wise.
Other thing, you can eazely adapt the WiFi or Ethernet library to work it with the module, since in many way the TLG work the same way except for the fact that it communicate with Arduino using the serial port. So basically you adapt it to send the same stuff but Serial way.
The ENC28J60 is totally off subject since there is not TCPIP stacking built in so let's just pass that part, it's gonna require half of you Arduino programming space just for the external stacking.
But what I really like about the TLG unit, is that in fact it does not even need a Ardunio to work. I've tried to hook a GPS, a Bluetooth module, a external US Robotic Modem using a RS232 to ttl module, and many other serial device on the TLG serial port, and they all worked fine sending and receiving there stuff on the net. It's completely stand alone, the fact that Arduino can use it, is just a plus.
In fact, it even has a GPIO programmable from the network using telnet or locally sending AT command in the serial port. It's as simple to use then saying ATA to a modem when the phone ring.
So by the end, a simple web server saying Hello World take about 3k of program space. It require only 2 wires to communicate with Arduino AND considering the GPIO, you can say that you gain back one of the two wires on the TLG device side.
I'm the kind of guy who prefers module over shield, especially because I can choose what i can hook where. And to me this module is way way better the any shield I've tried so far.
Finally this module alone cost about 14$, compare to a minimum of 10$ for the W5100 shield + i don't know how much for the TP-Link WR702N Nano , but it has to be less then 6$ to beat the TLG unit.http://www.amazon.com/Ethernet-Shield-Micro-sd-Arduino-Duemilanove/dp/B00GIDHZHE/ref=sr_1_5?s=electronics&ie=UTF8&qid=1387578646&sr=1-5&keywords=w5100+ethernet+shield
20 buck on amazon, Nah, not worth it Sorryhttp://www.amazon.com/TP-LINK-TL-WR702N-Wireless-Repeater-150Mpbs/dp/B007PTCFFW
For the WR702N plus the W5100 shield, I get 2 TLG unit an extra module of my choice, all that shipping included.
So i might conclude by saying for those who prefer shield that the adapter shield is 15$, the TLG module is usually around 14$ So for the same price you have the TLG set(shield + module). But to me because the TLG unit is so stand alone, you get more for your money with the TLG option. You will learn more, and Have more fun.
But, if your the Mac kinda persone, and you just want to hook and look at it work, with out work, go for the W5100, it's ease to use all is ready and there is no challenge, but also nothing to learn.
I'm the PC kinda guy, I like to build program and learn stuff. Every one is different.