Thanks, this is very helpful.
How important do you guys consider the 7" display (like on the Siglent SDS1202X-E and the Rigol DS1054Z) vs. a 5.6" (like on the Rigol DS1102E)? In addition to the additional features... seems like the larger higher res screen would be nice--and worth the extra money alone. But then again maybe not that big of a deal?
This kind of topic always get heated quite fast. Be it Rigol, Siglent or Tek, there will always be pros and cons about each brand and products.
In the end, it's about you and your needs. The point is not "which is the best ~400$ scope", it is:
- Is the TDS220 still doing what you need it to do?
- Would the Rigol DS1102E bring value in your typical day?
- Would a bigger [Rigol DS1054Z or Siglent SDS1202X-E] scope be worth it?
I really like nctnico's proposal: try to get the Rigol DS1102E for 125$, and then sell your TDS220 on ebay. You should get almost even and get that nice upgrade!
About screen size, yes, it typically matters

If you can easily see in one screen what a less capable scope requires much scrolling to see, it's a gain. For example, the Keysight 3000x and 4000x main differentiator is the much larger screen.