2011 Sony TV - I find it pretty much acceptable.
Timing depends on what you mean by boot time...
If you only need to use the same input as you turned off from last time you can be running in seven or eight seconds from a hard off situation (which I think is pretty good). Its a couple of seconds quicker from standby. Also if in Standby you can turn on the device that you want to watch (or in some cases press play) and from that end of the chain the surround amp and the TV will then be turned on and the right input selected*.
Even from hard power off it will display picture from last used source pretty quickly - HDMI (including HDCP negotiation) or even AVC HD broadcast (I'm in the UK) in under 8 seconds and I think the GOP length is pretty long. Channel selection is available from this point (although sluggish during the boot process) although not input selection.
Full boot up seems to take over 30s though including:
establishing a network connection,
logging into Skype.
identifying Audio System connected over HDMI*, turning it on and transferring sound output responsibilities.
identifying connected HDMI devices* (even those connected through the audio system) to allow direct selection of them from the TV UI.
other tasks such as populating the programme guide from the broadcast and finding DLNA servers are also taking place.
Interestingly the main menu continues to populate itself even after it is available (at about 30s), finishing at around 35-40s but selection of many items is available earlier. Programme guide and input selection also available from about 30s.
*I believe these processes are all using the HDMI CEC standard and would also work between non Sony devices but I haven't personally tested it. I have PS3 (only works with slim), Sony Blu-ray and Sony Surround Sound Receiver.
Disclaimer - Former Sony TV Product Planner. No current commercial relationship with Sony and I bought the TV and the surround receiver albeit with staff discount.
Note that while very much an Internet TV with iPlayer (BBC catch up), Lovefilm (UK Netflix equivalent including postal discs and streaming), MUBI, music services, DLNA capability, Skype etc. (and Sony's Premium Movie store and music subscription services) the Sony TVs are not sold as SmartTV and the services are very much directed towards being video content rather than apps. There is an Opera based browser but I would never bother using it.
The added cost of hardware for these additional services is almost nothing on models without wifi and without the Skype camera (cost of the video encoding is within the camera not the TV hardware everyone must pay for). Making more models without the features would reduce the value of those with the features by reducing the number of potential users and therefore the content providers interest. Outside the US the market for monitors rather than TVs is small even if many then connect a STB. Also the fact that features are built into the TV doesn't mean that if you wanted to upgrade in 5 years you need to replace the screen, just buy a new Internet box then. I have my doubts about whether the proprietary upgrade path Samsung is now creating will ever be used as the number of potential upgraders is probably not that great so will the upgrades come to market? It also indicates that they expect many services not to be available on the current TVs without upgrade which isn't the best way to maximise the platform size which is the key to getting the good content there, its very much hardware thinking.
My view and I think that of many in Sony was that the Internet features aren't necessarily to make people buy a new TV (there are Blu-rays and net box options for about GBP100 for adding the feature) but that if you are buying a new TV wouldn't you rather have the one with these features available at a similar cost or small premium.