Before buying anything I should know?

I have a Roku3 and am debating a Tablo (although peoples comments of speed issues makes me debate that) Is there anything else that people wish they had known before purchasing?

Tablo is a very good (and evolving) OTA DVR solution.  In fact, I think TabloTV has the competition on the run right now.  In some cases, solutions that had gone dormant have suddenly awakened and decided that maybe they should liven things up… and all (IMHO) thanks to Tablo.  But IMHO, the way they treated/treat their customers doesn’t bode well for Simple.TV, Tivo Roamio and Channel Master, but with that said, some are quite satisified with the alternatives to TabloTV.  Do your research and then decide.

(hoping Tablo wins that decision)

Keep in mind that forums, especially support forums, are typically filled with people who have problems, complaints or wishes. You don’t find support forums loaded with 150% satisfied customers who have zero complaints.

I have my own, but also realize it’s a growing bleeding-edge device and software. it’s getting better, the company pays attention. 

There are options besides Roku for playing Tablo - all have their own pros and cons. Chromecast is fast and pretty trouble-free for the most part but lacks some of the fanciness of Roku, for example. 
In any case, a purchase direct from Tablo OR comes with the possibility of return. Amazon has a pretty generous policy that way. Since you have one possible playback device already (Roku) you have little to lose except time.
There are things I wish were different, but honestly, I could say that about most things I buy anyway. The bigger things don’t prevent me from using or enjoying it. (at least as long as our Internet is up! If that goes down, the web app, which you must use if you don’t have a 7" tablet or an Apple device, won’t see your Tablo to control it)

Does that mean I have to have one of those devices to control it and the Roku can be used for playback?

I have my Tabol for about 3 weeks now (also using Roku3).  Couple of things did bother me a bit but in general I am happy and will but it again.

1. speed - but get used to it now  
2. no button to record live tv from Roku - you can do so using other device such as you smart phone though; I also assume the new interface will “fix” the issue
3. not 100% sure but it seems some people have issue watch sport event on 1080 tv with roku3 - My tv is 720 and i don"t have any issue  

good luck

I’ve had the Tablo for a couple weeks now and it’s working great with a Roku 3.

You will need a web browser to configure the settings but after that you don’t need one.

You can schedule shows to be recorded from the Roku.

The load speeds are a couple seconds.

Features I would like in the future:
-Faster load times
-Grid for live TV with the current show playing
-Button to record live shows

These aren’t deal breakers for me.

Before I purchased my Tablo, I made sure I had a “good” antenna with strong signal strength to pull in as many OTA channels as possible. I tested about 4 different antennae in different locations in my home to ensure I could watch OTA HD TV.  I’m was very happy with the results and Tablo complimented my viewing preferences.

If you are not sure if you need a 2 tuner or 4 tuner get the 4 tuner. I started out with the 2 tuner and had too many recording conflicts. So far zero with the 4 tuner.