Roku recently begin shipping their 2nd generation of 4K/UHD Roku streaming/media players. Note that while the main focus of these Roku units is their streaming functions, the flag-ship model can also play videos stored on local media. The Roku 4 came out in late 2015 and was their first attempt to produce a 4K player. It had a number of issues and limitations, some of which were addressed via subsequent firmware updates, but some were never addressed and in fact a few are carried over to the new series of 4K players.
Roku web site for their current line-up of players is at:
https://www.roku.com/productsThe Roku Premiere ($79.99) is the entry-level 4K player, the Premiere + ($99.99) is the mid-level model that adds HDR support, and the Ultra ($129.99) is the flagship model that adds voice search, remote finder and optical digital audio output.
The fan noise and heat issues of the original Roku 4 seem to have been addressed with the new models. However, the new 4K models still insist on outputting 4K/UHD programming at 60Hz and for me this is an issue when the original content is 2160p @ 24Hz. This conversion to 60Hz introduces 3:2 pull-down which introduces image judder that your UHD display may not be able to correct. Also 60Hz is placing unnecessary bandwidth requirements on the HDMI connection. This latter item can be an issue for home theater owners using displays (e.g., projectors) with long HDMI cable runs where very few existing high speed HDMI cables have proven to offer reliable connections for HDMI 2.0 when the data rates approach the 18Gbps limit.