I wouldn't worry too much especially if this is your budget right now, can always save up. Ton of companies offer similar machines at that price range so it's not really them alone, really as long as your happy with it right now that's what matter. Hard to go by ratings b/c about 99% of them buying and reviewing like on Amazon are just moving up from preground drip or still using drip and got it as a wedding gift etc etc... so they don't really no better, but compared to what they do know and what they've been used to it's "better". I started with a Bar32 which is the samething internally as your EC155 and was fine with it.... till I played with a real grinder and machine lol. At that point I never knew the difference between pressurized and non-pressurized portafilters. Even saying that though, I made better drinks and coffee on that cheap little thing then Starbucks any day, fresh beans are the most important part and even if using a pressurized portafilter fresh beans make a huge difference. You even said it tasted great vs your normal coffee before, so just consider that
. I may have made a mistake, when you said you were pre heating the water I thought you meant using warm water in the tank, I think what you meant by that was turning on the machine or warm up right? 15 Bar bragging rights don't matter, pump could be 50 Bars lol, when actually running at the puck will usually see around 9 bars regardless of rating.
I had a Capresso 560, although it's not suitable for espresso grinding pretty much at all, it's perfect for a pressurized portafitler machine or for coarse needs like drip etc.
But since you asked, pry the cheapest entry setup that's good would be a Gaggia Classic which hovers usually just under $400 new (some are like $360 new on ebay) or refurbed from wholelattelove for like $280 shipped (for some reason on their website they charge more for refurbs lol). A Saeco Aroma is cheaper but comes pressurized and no 3 way valve, so you have to buy a regular portafilter for it, might as well just get a Classic and enjoy it's other advantages. And Baratza Preciso grinder is about the cheapest fully espresso capable grinder and also has very tiny retention vs some others around it's price range, which is around $300 new or $230 something like that refurbed from Baratza (they update their site every Thursday with refurb models). I've got a Crossland CC1 and Preciso which is about a $1k combo new. But you can even consider getting a hand grinder, you can pick up a cheap Hario Skerton or Slim and they can be modded to be used stepless, I got Slim on Amazon for like 30 bucks. But then you need to factor in some accessories, like group cleaning brush, decent tamper (rattleware make s a great cheap one), cleaning/descaling stuff like Cafiza etc. Or since you mentioned the large drinks you make, people even used tripple bottomless baskets for higher doses like 21+ grams, and make larger shots like 3+ oz, or just normal 2oz shots but with the extraction taste of that dose.
Thats the main difference, real espresso requires a very fine, yet consistant grind with trimodal/bimodal qualities, and that's where the cheaper grinders can't compete... or do. They can grind fine and even choke a machine, but that doesn't mean much. And it's the puck creating the back pressure vs the mechanism in a pressurized unit, so with the right grid and dose you'll get that thick real espresso extraction and crema.
But like I said if your happy and this is your budget range right now, don't think about it. It taste good too you right now and that's all that matters. But like I also mentioned before you should still be able to pull 2 oz shots with the double, or maybe an ounce and half each since these baskets aren't large enough. If you like the single taste better it may be over-extracting and you like that punchier bitter taste.
If you want to try, you can disassemble the basket like the pic I posted above (which you should anyway to clean periodically as it can get gunked up, I remember my pressure clip was sticking and not working). And then just use it w/o the pressure mechanism and plate and try using your Capresso to grind with it, who knows, may like it better and sorta get more of a real espresso extraction.
